improved sql parser.

src/main/java/com/alibaba/druid/sql/SQLUtils.java

@@ -857,7 +857,7 @@ public class SQLUtils {
 
         List<SQLExpr> parameters = x.getParameters();
         SQLCaseExpr caseExpr = new SQLCaseExpr();
-
+        caseExpr.setParent(x.getParent());
         caseExpr.setValueExpr(parameters.get(0));
 
         for (int i = 1; i + 1 < parameters.size(); i += 2) {

src/main/java/com/alibaba/druid/sql/ast/SQLHint.java

@@ -17,5 +17,5 @@ package com.alibaba.druid.sql.ast;
 
 
 public interface SQLHint extends SQLObject {
-
+    SQLHint clone();
 }

src/main/java/com/alibaba/druid/sql/ast/SQLParameter.java

@@ -117,4 +117,29 @@ public class SQLParameter extends SQLObjectImpl {
         }
         this.cursorName = cursorName;
     }
+
+    public SQLParameter clone() {
+        SQLParameter x = new SQLParameter();
+        if (name != null) {
+            x.setName(name.clone());
+        }
+        if (dataType != null) {
+            x.setDataType(dataType.clone());
+        }
+        if (defaultValue != null) {
+            x.setDefaultValue(defaultValue.clone());
+        }
+        x.paramType = paramType;
+        x.noCopy = noCopy;
+        x.constant = constant;
+        if (cursorName != null) {
+            x.setCursorName(cursorName.clone());
+        }
+        for (SQLParameter p : cursorParameters) {
+            SQLParameter p2 = p.clone();
+            p2.setParent(x);
+            x.cursorParameters.add(p2);
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/SQLStatement.java

@@ -21,4 +21,6 @@ public interface SQLStatement extends SQLObject {
     boolean isAfterSemi();
 
     void setAfterSemi(boolean afterSemi);
+
+    SQLStatement clone();
 }

src/main/java/com/alibaba/druid/sql/ast/SQLStatementImpl.java

@@ -56,4 +56,8 @@ public abstract class SQLStatementImpl extends SQLObjectImpl implements SQLState
     public void setAfterSemi(boolean afterSemi) {
         this.afterSemi = afterSemi;
     }
+
+    public SQLStatement clone() {
+        throw new UnsupportedOperationException(this.getClass().getName());
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryExpr.java

@@ -59,6 +59,10 @@ public class SQLBinaryExpr extends SQLExprImpl implements SQLLiteralExpr {
         return result;
     }
 
+    public SQLBinaryExpr clone() {
+        return new SQLBinaryExpr(value);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {

src/main/java/com/alibaba/druid/sql/ast/expr/SQLBooleanExpr.java

@@ -83,4 +83,8 @@ public class SQLBooleanExpr extends SQLExprImpl implements SQLExpr, SQLLiteralEx
     public SQLDataType computeDataType() {
         return DEFAULT_DATA_TYPE;
     }
+
+    public SQLBooleanExpr clone() {
+        return new SQLBooleanExpr(value);
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLDateExpr.java

@@ -31,6 +31,10 @@ public class SQLDateExpr extends SQLExprImpl implements SQLLiteralExpr {
 
     }
 
+    public SQLDateExpr(String literal) {
+        this.literal = literal;
+    }
+
     public String getLiteral() {
         return literal;
     }
@@ -75,4 +79,7 @@ public class SQLDateExpr extends SQLExprImpl implements SQLLiteralExpr {
         return true;
     }
 
+    public SQLDateExpr clone() {
+        return new SQLDateExpr(literal);
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLDefaultExpr.java

@@ -39,4 +39,8 @@ public class SQLDefaultExpr extends SQLExprImpl implements SQLLiteralExpr {
     public String toString() {
         return "DEFAULT";
     }
+
+    public SQLDefaultExpr clone() {
+        return new SQLDefaultExpr();
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLHexExpr.java

@@ -80,4 +80,8 @@ public class SQLHexExpr extends SQLExprImpl implements SQLLiteralExpr {
     public byte[] toBytes() {
         return HexBin.decode(this.hex);
     }
+
+    public SQLHexExpr clone () {
+        return new SQLHexExpr(hex);
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLInListExpr.java

@@ -44,6 +44,20 @@ public class SQLInListExpr extends SQLExprImpl implements Serializable {
         this.not = not;
     }
 
+    public SQLInListExpr clone() {
+        SQLInListExpr x = new SQLInListExpr();
+        x.not = not;
+        if (expr != null) {
+            x.setExpr(expr.clone());
+        }
+        for (SQLExpr e : targetList) {
+            SQLExpr e2 = e.clone();
+            e2.setParent(x);
+            x.targetList.add(e2);
+        }
+        return x;
+    }
+
     public boolean isNot() {
         return this.not;
     }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLInSubQueryExpr.java

@@ -35,6 +35,18 @@ public class SQLInSubQueryExpr extends SQLExprImpl implements Serializable {
 
     }
 
+    public SQLInSubQueryExpr clone() {
+        SQLInSubQueryExpr x = new SQLInSubQueryExpr();
+        x.not = not;
+        if (expr != null) {
+            x.setExpr(expr.clone());
+        }
+        if (subQuery != null) {
+            x.setSubQuery(subQuery.clone());
+        }
+        return x;
+    }
+
     public boolean isNot() {
         return not;
     }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLListExpr.java

@@ -75,4 +75,14 @@ public class SQLListExpr extends SQLExprImpl {
         return true;
     }
 
+    public SQLListExpr clone() {
+        SQLListExpr x = new SQLListExpr();
+        for (SQLExpr item : items) {
+            SQLExpr item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+        return x;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLLiteralExpr.java

@@ -18,5 +18,5 @@ package com.alibaba.druid.sql.ast.expr;
 import com.alibaba.druid.sql.ast.SQLExpr;
 
 public interface SQLLiteralExpr extends SQLExpr {
-    
+    SQLLiteralExpr clone();
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLNumericLiteralExpr.java

@@ -26,4 +26,6 @@ public abstract class SQLNumericLiteralExpr extends SQLExprImpl implements SQLLi
     public abstract Number getNumber();
 
     public abstract void setNumber(Number number);
+
+    public abstract SQLNumericLiteralExpr clone();
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLTextLiteralExpr.java

@@ -67,4 +67,6 @@ public abstract class SQLTextLiteralExpr extends SQLExprImpl implements SQLLiter
         }
         return true;
     }
+
+    public abstract SQLTextLiteralExpr clone();
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLBlockStatement.java

@@ -32,6 +32,8 @@ public class SQLBlockStatement extends SQLStatementImpl {
 
     private List<SQLStatement> statementList = new ArrayList<SQLStatement>();
 
+    public SQLStatement exception;
+
     public List<SQLStatement> getStatementList() {
         return statementList;
     }
@@ -48,8 +50,6 @@ public class SQLBlockStatement extends SQLStatementImpl {
         this.labelName = labelName;
     }
 
-    public SQLStatement exception;
-
     @Override
     public void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -86,4 +86,28 @@ public class SQLBlockStatement extends SQLStatementImpl {
     public void setEndLabel(String endLabel) {
         this.endLabel = endLabel;
     }
+
+    public SQLBlockStatement clone() {
+        SQLBlockStatement x = new SQLBlockStatement();
+        x.labelName = labelName;
+        x.endLabel = endLabel;
+
+        for (SQLParameter p : parameters) {
+            SQLParameter p2 = p.clone();
+            p2.setParent(x);
+            x.parameters.add(p2);
+        }
+
+        for (SQLStatement stmt : statementList) {
+            SQLStatement stmt2 = stmt.clone();
+            stmt2.setParent(x);
+            x.statementList.add(stmt2);
+        }
+
+        if (exception != null) {
+            x.setException(exception.clone());
+        }
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLCommitStatement.java

@@ -35,6 +35,24 @@ public class SQLCommitStatement extends SQLStatementImpl {
     private SQLExpr transactionName;
     private SQLExpr delayedDurability;
 
+    public SQLCommitStatement clone() {
+        SQLCommitStatement x = new SQLCommitStatement();
+        x.write = write;
+        x.wait = wait;
+        x.immediate = immediate;
+        x.work = work;
+        x.chain = chain;
+        x.release = release;
+
+        if(transactionName != null) {
+            x.setTransactionName(transactionName.clone());
+        }
+        if (delayedDurability != null) {
+            x.setDelayedDurability(delayedDurability.clone());
+        }
+        return x;
+    }
+
     public void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
             acceptChild(visitor, transactionName);

src/main/java/com/alibaba/druid/sql/ast/statement/SQLCreateFunctionStatement.java

@@ -25,7 +25,7 @@ import java.util.List;
 /**
  * Created by wenshao on 23/05/2017.
  */
-public class SQLCreateFunctionStatement extends SQLStatementImpl {
+public class SQLCreateFunctionStatement extends SQLStatementImpl implements SQLDDLStatement {
     private SQLName definer;
 
     private boolean            create     = true;
@@ -47,6 +47,38 @@ public class SQLCreateFunctionStatement extends SQLStatementImpl {
 
     private boolean            deterministic  = false;
 
+    public SQLCreateFunctionStatement clone() {
+        SQLCreateFunctionStatement x = new SQLCreateFunctionStatement();
+
+        if (definer != null) {
+            x.setDefiner(definer.clone());
+        }
+        x.create = create;
+        x.orReplace = orReplace;
+        if (name != null) {
+            x.setName(name.clone());
+        }
+        if (block != null) {
+            x.setBlock(block.clone());
+        }
+        for (SQLParameter p : parameters) {
+            SQLParameter p2 = p.clone();
+            p2.setParent(x);
+            x.parameters.add(p2);
+        }
+        x.javaCallSpec = javaCallSpec;
+        if (authid != null) {
+            x.setAuthid(authid.clone());
+        }
+        if (returnDataType != null) {
+            x.setReturnDataType(returnDataType.clone());
+        }
+        x.comment = comment;
+        x.deterministic = deterministic;
+
+        return x;
+    }
+
     @Override
     public void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {

src/main/java/com/alibaba/druid/sql/ast/statement/SQLCreateIndexStatement.java

@@ -135,4 +135,23 @@ public class SQLCreateIndexStatement extends SQLStatementImpl implements SQLDDLS
 
         return null;
     }
+
+
+    public SQLCreateIndexStatement clone() {
+        SQLCreateIndexStatement x = new SQLCreateIndexStatement();
+        if (name != null) {
+            x.setName(name.clone());
+        }
+        if (table != null) {
+            x.setTable(table.clone());
+        }
+        for (SQLSelectOrderByItem item : items) {
+            SQLSelectOrderByItem item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+        x.type = type;
+        x.using = using;
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLCreateSequenceStatement.java

@@ -26,7 +26,7 @@ import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 /**
  * Created by wenshao on 16/9/14.
  */
-public class SQLCreateSequenceStatement extends SQLStatementImpl {
+public class SQLCreateSequenceStatement extends SQLStatementImpl implements SQLDDLStatement {
     private SQLName name;
 
     private SQLExpr startWith;

src/main/java/com/alibaba/druid/sql/ast/statement/SQLCreateViewStatement.java

@@ -280,4 +280,40 @@ public class SQLCreateViewStatement extends SQLStatementImpl implements SQLDDLSt
             }
         }
     }
+
+
+    public SQLCreateViewStatement clone() {
+        SQLCreateViewStatement x = new SQLCreateViewStatement();
+
+        x.orReplace = orReplace;
+        x.force = force;
+        if (subQuery != null) {
+            x.setSubQuery(subQuery.clone());
+        }
+        x.ifNotExists = ifNotExists;
+
+        x.algorithm = algorithm;
+        if (definer != null) {
+            x.setDefiner(definer.clone());
+        }
+        x.sqlSecurity = sqlSecurity;
+        if (tableSource != null) {
+            x.setTableSource(tableSource.clone());
+        }
+        for (SQLTableElement column : columns) {
+            SQLTableElement column2 = column.clone();
+            column2.setParent(x);
+            x.columns.add(column2);
+        }
+        x.withCheckOption = withCheckOption;
+        x.withCascaded = withCascaded;
+        x.withLocal = withLocal;
+        x.withReadOnly = withReadOnly;
+
+        if (comment != null) {
+            x.setComment(comment.clone());
+        }
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLErrorLoggingClause.java

@@ -60,4 +60,18 @@ public class SQLErrorLoggingClause extends SQLObjectImpl {
         this.limit = limit;
     }
 
+    public SQLErrorLoggingClause clone() {
+        SQLErrorLoggingClause x = new SQLErrorLoggingClause();
+        if (into != null) {
+            x.setInto(into.clone());
+        }
+        if (simpleExpression != null) {
+            x.setSimpleExpression(simpleExpression.clone());
+        }
+        if (limit != null) {
+            x.setLimit(limit.clone());
+        }
+        return x;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLExprHint.java

@@ -52,4 +52,11 @@ public class SQLExprHint extends SQLObjectImpl implements SQLHint {
         visitor.endVisit(this);
     }
 
+    public SQLExprHint clone() {
+        SQLExprHint x = new SQLExprHint();
+        if (expr != null) {
+            x.setExpr(expr.clone());
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLExprTableSource.java

@@ -223,4 +223,20 @@ public class SQLExprTableSource extends SQLTableSourceImpl {
         }
         return null;
     }
+
+    public SQLTableSource findTableSourceWithColumn(String columnName) {
+        if (schemaObject == null) {
+            return null;
+        }
+
+        SQLStatement stmt = schemaObject.getStatement();
+        if (stmt instanceof SQLCreateTableStatement) {
+            SQLCreateTableStatement createTableStmt = (SQLCreateTableStatement) stmt;
+            if (createTableStmt.findColumn(columnName) != null) {
+                return this;
+            }
+        }
+
+        return null;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLIfStatement.java

@@ -31,6 +31,26 @@ public class SQLIfStatement extends SQLStatementImpl {
     private List<ElseIf>       elseIfList = new ArrayList<ElseIf>();
     private Else               elseItem;
 
+    public SQLIfStatement clone() {
+        SQLIfStatement x = new SQLIfStatement();
+
+        for (SQLStatement stmt : statements) {
+            SQLStatement stmt2 = stmt.clone();
+            stmt2.setParent(x);
+            x.statements.add(stmt2);
+        }
+        for (ElseIf o : elseIfList) {
+            ElseIf o2 = o.clone();
+            o2.setParent(x);
+            x.elseIfList.add(o2);
+        }
+        if (elseItem != null) {
+            x.setElseItem(elseItem.clone());
+        }
+
+        return x;
+    }
+
     @Override
     public void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -111,6 +131,21 @@ public class SQLIfStatement extends SQLStatementImpl {
             }
             this.condition = condition;
         }
+
+        public ElseIf clone() {
+            ElseIf x = new ElseIf();
+
+            if (condition != null) {
+                x.setCondition(condition.clone());
+            }
+            for (SQLStatement stmt : statements) {
+                SQLStatement stmt2 = stmt.clone();
+                stmt2.setParent(x);
+                x.statements.add(stmt2);
+            }
+
+            return x;
+        }
     }
 
     public static class Else extends SQLObjectImpl {
@@ -133,5 +168,14 @@ public class SQLIfStatement extends SQLStatementImpl {
             this.statements = statements;
         }
 
+        public Else clone() {
+            Else x = new Else();
+            for (SQLStatement stmt : statements) {
+                SQLStatement stmt2 = stmt.clone();
+                stmt2.setParent(x);
+                x.statements.add(stmt2);
+            }
+            return x;
+        }
     }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLInsertInto.java

@@ -36,6 +36,27 @@ public abstract class SQLInsertInto extends SQLObjectImpl {
 
     }
 
+    public void cloneTo(SQLInsertInto x) {
+        if (tableSource != null) {
+            x.setTableSource(tableSource.clone());
+        }
+        for (SQLExpr column : columns) {
+            SQLExpr column2 = column.clone();
+            column2.setParent(x);
+            x.columns.add(column2);
+        }
+        if (query != null) {
+            x.setQuery(query.clone());
+        }
+        for (ValuesClause v : valuesList) {
+            ValuesClause v2 = v.clone();
+            v2.setParent(x);
+            x.valuesList.add(v2);
+        }
+    }
+
+    public abstract SQLInsertInto clone();
+
     public String getAlias() {
         return tableSource.getAlias();
     }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLInsertStatement.java

@@ -34,6 +34,19 @@ public class SQLInsertStatement extends SQLInsertInto implements SQLStatement {
 
     }
 
+    public void cloneTo(SQLInsertStatement x) {
+        super.cloneTo(x);
+        x.dbType = dbType;
+        x.upsert = upsert;
+        x.afterSemi = afterSemi;
+    }
+
+    public SQLInsertStatement clone() {
+        SQLInsertStatement x = new SQLInsertStatement();
+        cloneTo(x);
+        return x;
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -62,6 +75,14 @@ public class SQLInsertStatement extends SQLInsertInto implements SQLStatement {
             this(new ArrayList<SQLExpr>());
         }
 
+        public ValuesClause clone() {
+            ValuesClause x = new ValuesClause(new ArrayList<SQLExpr>(this.values.size()));
+            for (SQLExpr v : values) {
+                x.addValue(v);
+            }
+            return x;
+        }
+
         public ValuesClause(List<SQLExpr> values){
             this.values = values;
             for (int i = 0; i < values.size(); ++i) {

src/main/java/com/alibaba/druid/sql/ast/statement/SQLJoinTableSource.java

@@ -285,6 +285,10 @@ public class SQLJoinTableSource extends SQLTableSourceImpl implements SQLReplace
         if (right instanceof SQLJoinTableSource) {
             SQLJoinTableSource rightJoin = (SQLJoinTableSource) right;
 
+            if (rightJoin.joinType != JoinType.COMMA && rightJoin.joinType != JoinType.INNER_JOIN) {
+                return;
+            }
+
             SQLTableSource a = left;
             SQLTableSource b = rightJoin.getLeft();
             SQLTableSource c = rightJoin.getRight();
@@ -384,4 +388,20 @@ public class SQLJoinTableSource extends SQLTableSourceImpl implements SQLReplace
         return null;
     }
 
+    @Override
+    public SQLTableSource findTableSourceWithColumn(String columnName) {
+        if (left != null) {
+            SQLTableSource tableSource = left.findTableSourceWithColumn(columnName);
+            if (tableSource != null) {
+                return tableSource;
+            }
+        }
+
+        if (right != null) {
+            return right.findTableSourceWithColumn(columnName);
+        }
+
+        return null;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLReturnStatement.java

@@ -49,4 +49,12 @@ public class SQLReturnStatement extends SQLStatementImpl {
         }
         visitor.endVisit(this);
     }
+
+    public SQLReturnStatement clone() {
+        SQLReturnStatement x = new SQLReturnStatement();
+        if (expr != null) {
+            x.setExpr(expr.clone());
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectGroupByClause.java

@@ -83,6 +83,17 @@ public class SQLSelectGroupByClause extends SQLObjectImpl {
     }
 
     public SQLSelectGroupByClause clone() {
-        throw new UnsupportedOperationException();
+        SQLSelectGroupByClause x = new SQLSelectGroupByClause();
+        for (SQLExpr item : items) {
+            SQLExpr item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+        if (having != null) {
+            x.setHaving(having.clone());
+        }
+        x.withRollUp = withRollUp;
+        x.withCube = withCube;
+        return x;
     }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectItem.java

@@ -62,10 +62,10 @@ public class SQLSelectItem extends SQLObjectImpl implements SQLReplaceable {
     }
 
     public void setExpr(SQLExpr expr) {
-        this.expr = expr;
         if (expr != null) {
             expr.setParent(this);
         }
+        this.expr = expr;
     }
 
     public String computeAlias() {
@@ -151,7 +151,7 @@ public class SQLSelectItem extends SQLObjectImpl implements SQLReplaceable {
         SQLSelectItem x = new SQLSelectItem();
         x.alias = alias;
         if (expr != null) {
-            x.expr = expr.clone();
+            x.setExpr(expr.clone());
         }
         x.connectByRoot = connectByRoot;
         return x;

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectQueryBlock.java

@@ -438,6 +438,13 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         return findTableSource(from, alias);
     }
 
+    public SQLTableSource findTableSourceWithColumn(String column) {
+        if (from == null) {
+            return null;
+        }
+        return from.findTableSourceWithColumn(column);
+    }
+
     private static SQLTableSource findTableSource(SQLTableSource from, String alias) {
         if (from == null || alias == null) {
             return null;
@@ -489,6 +496,14 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         return null;
     }
 
+    public SQLColumnDefinition findColumn(String columnName) {
+        if (from == null) {
+            return null;
+        }
+
+        return from.findColumn(columnName);
+    }
+
     public void addCondition(SQLExpr expr) {
         if (expr == null) {
             return;

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectStatement.java

@@ -73,4 +73,19 @@ public class SQLSelectStatement extends SQLStatementImpl {
     public void setHeadHints(List<SQLCommentHint> headHints) {
         this.headHints = headHints;
     }
+
+    public SQLSelectStatement clone() {
+        SQLSelectStatement x = new SQLSelectStatement();
+        if (select != null) {
+            x.setSelect(select.clone());
+        }
+        if (headHints != null) {
+            for (SQLCommentHint h : headHints) {
+                SQLCommentHint h2 = h.clone();
+                h2.setParent(x);
+                x.headHints.add(h2);
+            }
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSetStatement.java

@@ -91,4 +91,21 @@ public class SQLSetStatement extends SQLStatementImpl {
             item.output(buf);
         }
     }
+
+    public SQLSetStatement clone() {
+        SQLSetStatement x = new SQLSetStatement();
+        for (SQLAssignItem item : items) {
+            SQLAssignItem item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+        if (hints != null) {
+            for (SQLCommentHint hint : hints) {
+                SQLCommentHint h2 = hint.clone();
+                h2.setParent(x);
+                x.hints.add(h2);
+            }
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLTableSource.java

@@ -38,4 +38,5 @@ public interface SQLTableSource extends SQLObject {
     void setFlashback(SQLExpr flashback);
 
     SQLColumnDefinition findColumn(String columnName);
+    SQLTableSource findTableSourceWithColumn(String columnName);
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLTableSourceImpl.java

@@ -98,4 +98,8 @@ public abstract class SQLTableSourceImpl extends SQLObjectImpl implements SQLTab
     public SQLColumnDefinition findColumn(String columnName) {
         return null;
     }
+
+    public SQLTableSource findTableSourceWithColumn(String columnName) {
+        return null;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLWhileStatement.java

@@ -68,4 +68,19 @@ public class SQLWhileStatement extends SQLStatementImpl {
 	public void setCondition(SQLExpr condition) {
 		this.condition = condition;
 	}
+
+	public SQLWhileStatement clone() {
+		SQLWhileStatement x = new SQLWhileStatement();
+
+		if (condition != null) {
+			x.setCondition(condition.clone());
+		}
+		for (SQLStatement stmt : statements) {
+			SQLStatement stmt2 = stmt.clone();
+			stmt2.setParent(x);
+			x.statements.add(stmt2);
+		}
+		x.labelName = labelName;
+		return x;
+	}
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/MySqlForceIndexHint.java

@@ -27,4 +27,9 @@ public class MySqlForceIndexHint extends MySqlIndexHintImpl {
         visitor.endVisit(this);
     }
 
+    public MySqlForceIndexHint clone() {
+        MySqlForceIndexHint x = new MySqlForceIndexHint();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/MySqlIgnoreIndexHint.java

@@ -27,4 +27,9 @@ public class MySqlIgnoreIndexHint extends MySqlIndexHintImpl {
         visitor.endVisit(this);
     }
 
+    public MySqlIgnoreIndexHint clone() {
+        MySqlIgnoreIndexHint x = new MySqlIgnoreIndexHint();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/MySqlIndexHintImpl.java

@@ -46,4 +46,14 @@ public abstract class MySqlIndexHintImpl extends MySqlObjectImpl implements MySq
         this.indexList = indexList;
     }
 
+    public abstract MySqlIndexHintImpl clone();
+
+    public void cloneTo(MySqlIndexHintImpl x) {
+        x.option = option;
+        for (SQLName name : indexList) {
+            SQLName name2 = name.clone();
+            name2.setParent(x);
+            x.indexList.add(name2);
+        }
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/MySqlUseIndexHint.java

@@ -27,4 +27,9 @@ public class MySqlUseIndexHint extends MySqlIndexHintImpl {
         visitor.endVisit(this);
     }
 
+    public MySqlUseIndexHint clone() {
+        MySqlUseIndexHint x = new MySqlUseIndexHint();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/statement/MySqlInsertStatement.java

@@ -34,6 +34,21 @@ public class MySqlInsertStatement extends SQLInsertStatement {
 
     private final List<SQLExpr> duplicateKeyUpdate = new ArrayList<SQLExpr>();
 
+    public void cloneTo(MySqlInsertStatement x) {
+        super.cloneTo(x);
+        x.lowPriority = lowPriority;
+        x.delayed = delayed;
+        x.highPriority = highPriority;
+        x.ignore = ignore;
+        x.rollbackOnFail = rollbackOnFail;
+
+        for (SQLExpr e : duplicateKeyUpdate) {
+            SQLExpr e2 = e.clone();
+            e2.setParent(x);
+            x.duplicateKeyUpdate.add(e2);
+        }
+    }
+
     public List<SQLExpr> getDuplicateKeyUpdate() {
         return duplicateKeyUpdate;
     }
@@ -102,4 +117,10 @@ public class MySqlInsertStatement extends SQLInsertStatement {
 
         visitor.endVisit(this);
     }
+
+    public SQLInsertStatement clone() {
+        MySqlInsertStatement x = new MySqlInsertStatement();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/transform/NameResolveVisitor.java

@@ -69,4 +69,32 @@ public class NameResolveVisitor extends OracleASTVisitorAdapter {
         }
         return true;
     }
+
+    public boolean visit(SQLPropertyExpr x) {
+        String ownerName = x.getOwnernName();
+        if (ownerName == null) {
+            return super.visit(x);
+        }
+
+        for (SQLObject parent = x.getParent(); parent != null; parent = parent.getParent()) {
+            if (parent instanceof SQLSelectQueryBlock) {
+                SQLSelectQueryBlock queryBlock = (SQLSelectQueryBlock) parent;
+                SQLTableSource tableSource = queryBlock.findTableSource(ownerName);
+                if (tableSource == null) {
+                    continue;
+                }
+
+                String alias = tableSource.getAlias();
+                if (tableSource != null
+                        && ownerName.equalsIgnoreCase(alias)
+                        && !ownerName.equals(alias)) {
+                    x.setOwner(alias);
+                }
+
+                break;
+            }
+        }
+
+        return super.visit(x);
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/OracleSQLObjectImpl.java

@@ -35,7 +35,7 @@ public abstract class OracleSQLObjectImpl extends SQLObjectImpl implements Oracl
     public abstract void accept0(OracleASTVisitor visitor);
 
     public OracleSQLObject clone() {
-        throw new UnsupportedOperationException();
+        throw new UnsupportedOperationException(this.getClass().getName());
     }
 
     public SQLDataType computeDataType() {

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/clause/OracleReturningClause.java

@@ -58,4 +58,21 @@ public class OracleReturningClause extends OracleSQLObjectImpl {
         visitor.endVisit(this);
     }
 
+    public OracleReturningClause clone() {
+        OracleReturningClause x = new OracleReturningClause();
+
+        for (SQLExpr item : items) {
+            SQLExpr item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+
+        for (SQLExpr v : values) {
+            SQLExpr v2 = v.clone();
+            v2.setParent(x);
+            x.values.add(v2);
+        }
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/clause/OracleStorageClause.java

@@ -34,6 +34,43 @@ public class OracleStorageClause extends OracleSQLObjectImpl {
     private FlashCacheType flashCache;
     private FlashCacheType cellFlashCache;
 
+    public OracleStorageClause clone() {
+        OracleStorageClause x = new OracleStorageClause();
+        if (initial != null) {
+            x.setInitial(initial.clone());
+        }
+        if (next != null) {
+            x.setNext(next.clone());
+        }
+        if (minExtents != null) {
+            x.setMinExtents(minExtents.clone());
+        }
+        if (maxExtents != null) {
+            x.setMinExtents(maxExtents.clone());
+        }
+        if (maxSize != null) {
+            x.setMaxSize(maxSize.clone());
+        }
+        if (pctIncrease != null) {
+            x.setPctIncrease(pctIncrease.clone());
+        }
+        if (freeLists != null) {
+            x.setFreeLists(freeLists.clone());
+        }
+        if (freeListGroups != null) {
+            x.setFreeListGroups(freeListGroups.clone());
+        }
+        if (bufferPool != null) {
+            x.setBufferPool(bufferPool.clone());
+        }
+        if (objno != null) {
+            x.setObjno(objno.clone());
+        }
+        x.flashCache = flashCache;
+        x.cellFlashCache = cellFlashCache;
+        return x;
+    }
+
     @Override
     public void accept0(OracleASTVisitor visitor) {
         if (visitor.visit(this)) {

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleBinaryDoubleExpr.java

@@ -95,4 +95,7 @@ public class OracleBinaryDoubleExpr extends SQLNumericLiteralExpr implements Ora
         this.setValue(number.doubleValue());
     }
 
+    public OracleBinaryDoubleExpr clone() {
+        return new OracleBinaryDoubleExpr(value);
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleBinaryFloatExpr.java

@@ -32,6 +32,10 @@ public class OracleBinaryFloatExpr extends SQLNumericLiteralExpr implements Orac
         this.value = value;
     }
 
+    public OracleBinaryFloatExpr clone() {
+        return new OracleBinaryFloatExpr(value);
+    }
+
     @Override
     public Number getNumber() {
         return value;

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleIntervalExpr.java

@@ -34,6 +34,19 @@ public class OracleIntervalExpr extends SQLExprImpl implements SQLLiteralExpr, O
 
     }
 
+    public OracleIntervalExpr clone() {
+        OracleIntervalExpr x = new OracleIntervalExpr();
+        if (value != null) {
+            x.setValue(value.clone());
+        }
+        x.type = type;
+        x.precision = precision;
+        x.factionalSecondsPrecision = factionalSecondsPrecision;
+        x.toType = toType;
+        x.toFactionalSecondsPrecision = toFactionalSecondsPrecision;
+        return x;
+    }
+
     public SQLExpr getValue() {
         return this.value;
     }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleCheck.java

@@ -84,4 +84,21 @@ public class OracleCheck extends SQLCheck implements OracleConstraint, OracleSQL
         this.using = using;
     }
 
+    public void cloneTo(OracleCheck x) {
+        super.cloneTo(x);
+        if (using != null) {
+            x.setUsing(using.clone());
+        }
+        if (exceptionsInto != null) {
+            x.setExceptionsInto(exceptionsInto.clone());
+        }
+        x.initially = initially;
+        x.deferrable = deferrable;
+    }
+
+    public OracleCheck clone() {
+        OracleCheck x = new OracleCheck();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleConstraint.java

@@ -48,4 +48,6 @@ public interface OracleConstraint extends OracleSQLObject, SQLConstraint, SQLTab
     public static enum Initially {
         DEFERRED, IMMEDIATE
     }
+
+    OracleConstraint clone();
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleExceptionStatement.java

@@ -72,6 +72,18 @@ public class OracleExceptionStatement extends OracleStatementImpl implements Ora
             visitor.endVisit(this);
         }
 
+        public Item clone() {
+            Item x = new Item();
+            if (when != null) {
+                x.setWhen(when.clone());
+            }
+            for (SQLStatement stmt : statements) {
+                SQLStatement stmt2 = stmt.clone();
+                stmt2.setParent(x);
+                x.statements.add(stmt2);
+            }
+            return x;
+        }
     }
 
     @Override
@@ -81,4 +93,14 @@ public class OracleExceptionStatement extends OracleStatementImpl implements Ora
         }
         visitor.endVisit(this);
     }
+
+    public OracleExceptionStatement clone() {
+        OracleExceptionStatement x = new OracleExceptionStatement();
+        for (Item item : items) {
+            Item item2 = item.clone();
+            item2.setParent(x);
+            x.items.add(item2);
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleForStatement.java

@@ -86,4 +86,24 @@ public class OracleForStatement extends OracleStatementImpl {
         }
         this.endLabel = endLabel;
     }
+
+    public OracleForStatement clone() {
+        OracleForStatement x = new OracleForStatement();
+        if (index != null) {
+            x.setIndex(index.clone());
+        }
+        if (range != null) {
+            x.setRange(range.clone());
+        }
+        for (SQLStatement stmt : statements) {
+            SQLStatement stmt2 = stmt.clone();
+            stmt2.setParent(x);
+            x.statements.add(stmt2);
+        }
+        x.all = all;
+        if (endLabel != null) {
+            x.setEndLabel(endLabel.clone());
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleForeignKey.java

@@ -86,4 +86,21 @@ public class OracleForeignKey extends SQLForeignKeyImpl implements OracleConstra
         this.using = using;
     }
 
+    public void cloneTo(OracleForeignKey x) {
+        super.cloneTo(x);
+        if (using != null) {
+            x.setUsing(using.clone());
+        }
+        if (exceptionsInto != null) {
+            x.setExceptionsInto(exceptionsInto.clone());
+        }
+        x.initially = initially;
+        x.deferrable = deferrable;
+    }
+
+    public OracleForeignKey clone() {
+        OracleForeignKey x = new OracleForeignKey();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleInsertStatement.java

@@ -28,9 +28,24 @@ import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class OracleInsertStatement extends SQLInsertStatement implements OracleStatement {
 
-    private OracleReturningClause    returning;
+    private OracleReturningClause returning;
     private SQLErrorLoggingClause errorLogging;
-    private List<SQLHint>            hints = new ArrayList<SQLHint>();
+    private List<SQLHint>         hints = new ArrayList<SQLHint>();
+
+    public void cloneTo(OracleInsertStatement x) {
+        super.cloneTo(x);
+        if (returning != null) {
+            x.setReturning(returning.clone());
+        }
+        if (errorLogging != null) {
+            x.setErrorLogging(errorLogging.clone());
+        }
+        for (SQLHint hint : hints) {
+            SQLHint h2 = hint.clone();
+            h2.setParent(x);
+            x.hints.add(h2);
+        }
+    }
 
     public List<SQLHint> getHints() {
         return hints;
@@ -77,4 +92,10 @@ public class OracleInsertStatement extends SQLInsertStatement implements OracleS
     public void output(StringBuffer buf) {
     	new OracleOutputVisitor(buf).visit(this);
     }
+
+    public OracleInsertStatement clone() {
+        OracleInsertStatement x = new OracleInsertStatement();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleMultiInsertStatement.java

@@ -198,5 +198,21 @@ public class OracleMultiInsertStatement extends OracleStatementImpl {
 
             visitor.endVisit(this);
         }
+
+        public void cloneTo(InsertIntoClause x) {
+            super.cloneTo(x);
+            if (returning != null) {
+                x.setReturning(returning.clone());
+            }
+            if (errorLogging != null) {
+                x.setErrorLogging(errorLogging.clone());
+            }
+        }
+
+        public InsertIntoClause clone() {
+            InsertIntoClause x = new InsertIntoClause();
+            cloneTo(x);
+            return x;
+        }
     }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleSelectRestriction.java

@@ -47,6 +47,14 @@ public abstract class OracleSelectRestriction extends OracleSQLObjectImpl {
 
             visitor.endVisit(this);
         }
+
+        public CheckOption clone() {
+            CheckOption x = new CheckOption();
+            if (constraint != null) {
+                x.setConstraint(constraint.clone());
+            }
+            return x;
+        }
     }
 
     public static class ReadOnly extends OracleSelectRestriction {
@@ -60,5 +68,12 @@ public abstract class OracleSelectRestriction extends OracleSQLObjectImpl {
 
             visitor.endVisit(this);
         }
+
+        public ReadOnly clone() {
+            ReadOnly x = new ReadOnly();
+            return x;
+        }
     }
+
+
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleUnique.java

@@ -83,4 +83,22 @@ public class OracleUnique extends SQLUnique implements OracleConstraint, OracleS
         this.initially = initially;
     }
 
+    public void cloneTo(OracleUnique x) {
+        super.cloneTo(x);
+        if (using != null) {
+            x.setUsing(using.clone());
+        }
+        if (exceptionsInto != null) {
+            x.setExceptionsInto(exceptionsInto.clone());
+        }
+        x.initially = initially;
+        x.deferrable = deferrable;
+    }
+
+    public OracleUnique clone() {
+        OracleUnique x = new OracleUnique();
+        cloneTo(x);
+        return x;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/ast/PGWithClause.java

@@ -48,4 +48,15 @@ public class PGWithClause extends PGSQLObjectImpl {
         }
         visitor.endVisit(this);
     }
+
+    public PGWithClause clone() {
+        PGWithClause x = new PGWithClause();
+        x.recursive = recursive;
+        for (PGWithQuery w : withQuery) {
+            PGWithQuery w2 = w.clone();
+            w2.setParent(x);
+            x.withQuery.add(w2);
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/ast/PGWithQuery.java

@@ -64,4 +64,22 @@ public class PGWithQuery extends PGSQLObjectImpl {
         }
         visitor.endVisit(this);
     }
+
+    public PGWithQuery clone() {
+        PGWithQuery x = new PGWithQuery();
+
+        if (name != null) {
+            x.setName(name.clone());
+        }
+        for (SQLExpr c : columns) {
+            SQLExpr c2 = c.clone();
+            c2.setParent(x);
+            x.columns.add(c);
+        }
+        if (query != null) {
+            x.setQuery(query.clone());
+        }
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/ast/expr/PGIntervalExpr.java

@@ -65,4 +65,12 @@ public class PGIntervalExpr extends SQLExprImpl implements SQLLiteralExpr,PGExpr
     protected void accept0(SQLASTVisitor visitor) {
         this.accept0((PGASTVisitor) visitor);
     }
+
+    public PGIntervalExpr clone() {
+        PGIntervalExpr x = new PGIntervalExpr();
+        if (value != null) {
+            x.setValue(value.clone());
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/ast/stmt/PGInsertStatement.java

@@ -31,6 +31,22 @@ public class PGInsertStatement extends SQLInsertStatement implements PGSQLStatem
     private SQLExpr            returning;
     private boolean			   defaultValues = false;
 
+    public void cloneTo(PGInsertStatement x) {
+        super.cloneTo(x);
+        if (with != null) {
+            x.setWith(with.clone());
+        }
+        for (ValuesClause v : valuesList) {
+            ValuesClause v2 = v.clone();
+            v2.setParent(x);
+            x.valuesList.add(v2);
+        }
+        if (returning != null) {
+            x.setReturning(returning.clone());
+        }
+        x.defaultValues = defaultValues;
+    }
+
     public SQLExpr getReturning() {
         return returning;
     }
@@ -96,4 +112,10 @@ public class PGInsertStatement extends SQLInsertStatement implements PGSQLStatem
 
         visitor.endVisit(this);
     }
+
+    public PGInsertStatement clone() {
+        PGInsertStatement x = new PGInsertStatement();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/SQLServerOutput.java

@@ -58,4 +58,21 @@ public class SQLServerOutput extends SQLServerObjectImpl {
         return selectList;
     }
 
+    public SQLServerOutput clone() {
+        SQLServerOutput x = new SQLServerOutput();
+        if (into != null) {
+            x.setInto(into.clone());
+        }
+        for (SQLExpr c : columns) {
+            SQLExpr c2 = c.clone();
+            c2.setParent(x);
+            x.columns.add(c2);
+        }
+        for (SQLSelectItem item : selectList) {
+            SQLSelectItem item2 = item.clone();
+            item2.setParent(x);
+            x.selectList.add(item2);
+        }
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/SQLServerTop.java

@@ -65,4 +65,13 @@ public class SQLServerTop extends SQLServerObjectImpl {
         visitor.endVisit(this);
     }
 
+    public SQLServerTop clone() {
+        SQLServerTop x = new SQLServerTop();
+        if (expr != null) {
+            x.setExpr(expr.clone());
+        }
+        x.percent = percent;
+        x.withTies = withTies;
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/stmt/SQLServerInsertStatement.java

@@ -33,6 +33,17 @@ public class SQLServerInsertStatement extends SQLInsertStatement implements SQLS
 
     private SQLServerOutput    output;
 
+    public void cloneTo(SQLServerInsertStatement x) {
+        super.cloneTo(x);
+        x.defaultValues = defaultValues;
+        if (top != null) {
+            x.setTop(top.clone());
+        }
+        if (output != null) {
+            x.setOutput(output.clone());
+        }
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         this.accept0((SQLServerASTVisitor) visitor);
@@ -76,4 +87,9 @@ public class SQLServerInsertStatement extends SQLInsertStatement implements SQLS
         this.top = top;
     }
 
+    public SQLServerInsertStatement clone() {
+        SQLServerInsertStatement x = new SQLServerInsertStatement();
+        cloneTo(x);
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/repository/SchemaRepository.java

@@ -17,10 +17,7 @@ package com.alibaba.druid.sql.repository;
 
 import com.alibaba.druid.DruidRuntimeException;
 import com.alibaba.druid.sql.SQLUtils;
-import com.alibaba.druid.sql.ast.SQLDataType;
-import com.alibaba.druid.sql.ast.SQLExpr;
-import com.alibaba.druid.sql.ast.SQLName;
-import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.*;
 import com.alibaba.druid.sql.ast.expr.SQLAggregateExpr;
 import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
@@ -32,7 +29,11 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStateme
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowCreateTableStatement;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitorAdapter;
+import com.alibaba.druid.sql.dialect.odps.ast.OdpsSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.odps.visitor.OdpsASTVisitorAdapter;
 import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleCreateTableStatement;
+import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleSelectTableReference;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitorAdapter;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitorAdapter;
@@ -50,6 +51,7 @@ public class SchemaRepository {
     private Schema defaultSchema;
     protected String dbType;
     protected SQLASTVisitor consoleVisitor;
+    protected SQLASTVisitor resolveVisitor;
 
     public SchemaRepository() {
 
@@ -60,8 +62,10 @@ public class SchemaRepository {
 
         if (JdbcConstants.MYSQL.equals(dbType)) {
             consoleVisitor = new MySqlConsoleSchemaVisitor();
+            resolveVisitor = new MySqlResolveVisitor();
         } else if (JdbcConstants.ORACLE.equals(dbType)) {
             consoleVisitor = new OracleConsoleSchemaVisitor();
+            resolveVisitor = new OracleResolveVisitor();
         } else {
             consoleVisitor = new DefaultConsoleSchemaVisitor();
         }
@@ -113,8 +117,15 @@ public class SchemaRepository {
             return getDefaultSchema();
         }
 
-        String normalizedName = SQLUtils.normalize(name)
-                .toLowerCase();
+        name = SQLUtils.normalize(name);
+        String normalizedName = name.toLowerCase();
+
+        if (getDefaultSchema() != null && defaultSchema.getName() == null) {
+            defaultSchema.setName(name);
+            schemas.put(normalizedName, defaultSchema);
+            return defaultSchema;
+        }
+
         Schema schema = schemas.get(normalizedName);
         if (schema == null) {
             schema = new Schema(this, name);
@@ -228,6 +239,16 @@ public class SchemaRepository {
         return getDefaultSchema().getViewCount();
     }
 
+    public String resolve(String input) {
+        List<SQLStatement> stmtList = SQLUtils.parseStatements(input, dbType);
+
+        for (SQLStatement stmt : stmtList) {
+            stmt.accept(resolveVisitor);
+        }
+
+        return SQLUtils.toSQLString(stmtList, dbType);
+    }
+
     public String console(String input) {
         try {
             StringBuffer buf = new StringBuffer();
@@ -300,85 +321,148 @@ public class SchemaRepository {
         return null;
     }
 
-    public SQLASTVisitor createResolveVisitor() {
-        if (JdbcConstants.MYSQL.equals(dbType)) {
-            return new MySqlResolveVisitor();
-        }
-
-        throw new DruidRuntimeException("dbType not support : " + dbType);
-    }
-
     public class MySqlResolveVisitor extends MySqlASTVisitorAdapter {
 
         public boolean visit(SQLExprTableSource x) {
-            if (x.getSchemaObject() != null) {
-                return false;
-            }
-
-            SQLExpr expr = x.getExpr();
-            if (expr instanceof SQLName) {
-                SchemaObject table = findTable((SQLName) expr);
-                if (table != null) {
-                    x.setSchemaObject(table);
-                }
-            }
+            resolve(this, x);
             return false;
         }
 
         public boolean visit(MySqlSelectQueryBlock x) {
-            SQLTableSource from = x.getFrom();
-            from.accept(this);
+            x.getFrom().accept(this);
 
-            List<SQLSelectItem> selectList = x.getSelectList();
+            resolve(this, x);
+            return super.visit(x);
+        }
+    }
 
-            List<SQLSelectItem> columns = new ArrayList<SQLSelectItem>();
-            for (int i = selectList.size() - 1; i >= 0; i--) {
-                SQLSelectItem selectItem = selectList.get(i);
-                SQLExpr expr = selectItem.getExpr();
-                if (expr instanceof SQLAllColumnExpr) {
-                    extractColumns(from, columns);
-                } else if (expr instanceof SQLPropertyExpr) {
-                    SQLPropertyExpr propertyExpr = (SQLPropertyExpr) expr;
-                    String ownerName = propertyExpr.getOwnernName();
-                    if (propertyExpr.getName().equals("*")) {
-                        SQLTableSource tableSource = x.findTableSource(ownerName);
-                        extractColumns(tableSource, columns);
-                    }
+    public class OracleResolveVisitor extends OracleASTVisitorAdapter {
+        public boolean visit(OracleSelectTableReference x) {
+            resolve(this, x);
+            return false;
+        }
 
-                    SQLColumnDefinition column = propertyExpr.getResolvedColumn();
-                    if (column != null) {
-                        continue;
-                    }
-                    SQLTableSource tableSource = x.findTableSource(propertyExpr.getOwnernName());
-                    if (tableSource != null) {
-                        column = tableSource.findColumn(propertyExpr.getName());
-                        if (column != null) {
-                            propertyExpr.setResolvedColumn(column);
-                        }
-                    }
-                } else if (expr instanceof SQLIdentifierExpr) {
-                    SQLIdentifierExpr identExpr = (SQLIdentifierExpr) expr;
-                    SQLColumnDefinition column = identExpr.getResolvedColumn();
-                    if (column != null) {
-                        continue;
-                    }
-                    column = from.findColumn(identExpr.getName());
-                    if (column != null) {
-                        identExpr.setResolvedColumn(column);
-                    }
+        public boolean visit(SQLExprTableSource x) {
+            resolve(this, x);
+            return false;
+        }
+
+        public boolean visit(OracleSelectQueryBlock x) {
+            x.getFrom().accept(this);
+
+            resolve(this, x);
+            return super.visit(x);
+        }
+
+        public boolean visit(SQLIdentifierExpr x) {
+            resolve(this, x);
+            return true;
+        }
+    }
+
+    public class OdpsResolveVisitor extends OdpsASTVisitorAdapter {
+
+        public boolean visit(SQLExprTableSource x) {
+            resolve(this, x);
+            return false;
+        }
+
+        public boolean visit(OdpsSelectQueryBlock x) {
+            resolve(this, x);
+            return super.visit(x);
+        }
+    }
+
+    private void resolve(SQLASTVisitor visitor, SQLIdentifierExpr x) {
+        SQLSelectQueryBlock queryBlock = null;
+        for (SQLObject parent = x.getParent(); parent != null; parent = parent.getParent()) {
+            if (parent instanceof SQLTableSource) {
+                return;
+            }
+            if (parent instanceof SQLSelectQueryBlock) {
+                queryBlock = (SQLSelectQueryBlock) parent;
+                break;
+            }
+        }
+
+        if (queryBlock == null) {
+            return;
+        }
+
+        String ident = x.getName();
+        SQLTableSource tableSource = queryBlock.findTableSourceWithColumn(ident);
+        if (tableSource != null) {
+            String alias = tableSource.computeAlias();
+            SQLPropertyExpr propertyExpr = new SQLPropertyExpr(alias, ident);
+            SQLUtils.replaceInParent(x, propertyExpr);
+        }
+    }
+
+    private void resolve(SQLASTVisitor visitor, SQLExprTableSource x) {
+        if (x.getSchemaObject() != null) {
+            return;
+        }
+
+        SQLExpr expr = x.getExpr();
+        if (expr instanceof SQLName) {
+            SchemaObject table = findTable((SQLName) expr);
+            if (table != null) {
+                x.setSchemaObject(table);
+            }
+        }
+    }
+
+    private void resolve(SQLASTVisitor visitor, SQLSelectQueryBlock x) {
+        SQLTableSource from = x.getFrom();
+        from.accept(visitor);
+
+        List<SQLSelectItem> selectList = x.getSelectList();
+
+        List<SQLSelectItem> columns = new ArrayList<SQLSelectItem>();
+        for (int i = selectList.size() - 1; i >= 0; i--) {
+            SQLSelectItem selectItem = selectList.get(i);
+            SQLExpr expr = selectItem.getExpr();
+            if (expr instanceof SQLAllColumnExpr) {
+                extractColumns(from, columns);
+            } else if (expr instanceof SQLPropertyExpr) {
+                SQLPropertyExpr propertyExpr = (SQLPropertyExpr) expr;
+                String ownerName = propertyExpr.getOwnernName();
+                if (propertyExpr.getName().equals("*")) {
+                    SQLTableSource tableSource = x.findTableSource(ownerName);
+                    extractColumns(tableSource, columns);
                 }
 
-                if (columns.size() > 0) {
-                    for (SQLSelectItem column : columns) {
-                        column.setParent(x);
+                SQLColumnDefinition column = propertyExpr.getResolvedColumn();
+                if (column != null) {
+                    continue;
+                }
+                SQLTableSource tableSource = x.findTableSource(propertyExpr.getOwnernName());
+                if (tableSource != null) {
+                    column = tableSource.findColumn(propertyExpr.getName());
+                    if (column != null) {
+                        propertyExpr.setResolvedColumn(column);
                     }
-
-                    selectList.remove(i);
-                    selectList.addAll(i, columns);
+                }
+            } else if (expr instanceof SQLIdentifierExpr) {
+                SQLIdentifierExpr identExpr = (SQLIdentifierExpr) expr;
+                SQLColumnDefinition column = identExpr.getResolvedColumn();
+                if (column != null) {
+                    continue;
+                }
+                column = from.findColumn(identExpr.getName());
+                if (column != null) {
+                    identExpr.setResolvedColumn(column);
                 }
             }
-            
-            return super.visit(x);
+
+            if (columns.size() > 0) {
+                for (SQLSelectItem column : columns) {
+                    column.setParent(x);
+                }
+
+                selectList.remove(i);
+                selectList.addAll(i, columns);
+            }
         }
     }
 
@@ -412,10 +496,6 @@ public class SchemaRepository {
         return null;
     }
 
-    public class OracleResolveVisitor extends OracleASTVisitorAdapter {
-
-    }
-
     public class MySqlConsoleSchemaVisitor extends MySqlASTVisitorAdapter {
         public boolean visit(SQLDropSequenceStatement x) {
             acceptDropSequence(x);
@@ -461,6 +541,13 @@ public class SchemaRepository {
             acceptAlterTable(x);
             return false;
         }
+
+
+        public boolean visit(SQLUseStatement x) {
+            String schema = x.getDatabase().getSimpleName();
+            setDefaultSchema(schema);
+            return false;
+        }
     }
 
     public class OracleConsoleSchemaVisitor extends OracleASTVisitorAdapter {
@@ -508,6 +595,12 @@ public class SchemaRepository {
             acceptAlterTable(x);
             return false;
         }
+
+        public boolean visit(SQLUseStatement x) {
+            String schema = x.getDatabase().getSimpleName();
+            setDefaultSchema(schema);
+            return false;
+        }
     }
 
     public class DefaultConsoleSchemaVisitor extends SQLASTVisitorAdapter {
@@ -575,7 +668,7 @@ public class SchemaRepository {
 
         SQLSelect select = x.getSelect();
         if (select != null) {
-            select.accept(createResolveVisitor());
+            select.accept(resolveVisitor);
 
             SQLSelectQueryBlock queryBlock = select.getFirstQueryBlock();
             if (queryBlock != null) {
@@ -601,7 +694,7 @@ public class SchemaRepository {
             return false;
         }
 
-        table = new SchemaObjectImpl(name, SchemaObjectType.Table, x);
+        table = new SchemaObjectImpl(name, SchemaObjectType.Table, x.clone());
         String name_lower = SQLUtils.normalize(name).toLowerCase();
         schema.objects.put(name_lower, table);
         return true;
@@ -632,7 +725,7 @@ public class SchemaRepository {
             return false;
         }
 
-        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.View, x);
+        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.View, x.clone());
         String name_lower = SQLUtils.normalize(name).toLowerCase();
         schema.objects.put(name_lower, object);
         return true;
@@ -644,7 +737,7 @@ public class SchemaRepository {
         Schema schema = findSchema(schemaName, true);
 
         String name = x.getName().getSimpleName();
-        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.Index);
+        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.Index, x.clone());
         String name_lower = SQLUtils.normalize(name).toLowerCase();
         schema.objects.put(name_lower, object);
 
@@ -656,7 +749,7 @@ public class SchemaRepository {
         Schema schema = findSchema(schemaName, true);
 
         String name = x.getName().getSimpleName();
-        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.Function);
+        SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.Function, x.clone());
         String name_lower = SQLUtils.normalize(name).toLowerCase();
         schema.functions.put(name_lower, object);
 

src/main/java/com/alibaba/druid/util/JdbcUtils.java

@@ -25,15 +25,8 @@ import java.io.Closeable;
 import java.io.InputStream;
 import java.io.PrintStream;
 import java.net.URL;
-import java.sql.Connection;
+import java.sql.*;
 import java.sql.Date;
-import java.sql.Driver;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.ResultSetMetaData;
-import java.sql.SQLException;
-import java.sql.Statement;
-import java.sql.Types;
 import java.util.*;
 
 /**
@@ -117,6 +110,30 @@ public final class JdbcUtils implements JdbcConstants {
         }
     }
 
+    public static void close(Blob x) {
+        if (x == null) {
+            return;
+        }
+
+        try {
+            x.free();
+        } catch (Exception e) {
+            LOG.debug("close error", e);
+        }
+    }
+
+    public static void close(Clob x) {
+        if (x == null) {
+            return;
+        }
+
+        try {
+            x.free();
+        } catch (Exception e) {
+            LOG.debug("close error", e);
+        }
+    }
+
     public static void printResultSet(ResultSet rs) throws SQLException {
         printResultSet(rs, System.out);
     }

src/main/java/com/alibaba/druid/util/Utils.java

@@ -200,7 +200,7 @@ public class Utils {
         if (className == null) {
             return null;
         }
-        
+
         try {
             return Class.forName(className);
         } catch (ClassNotFoundException e) {
@@ -236,7 +236,7 @@ public class Utils {
     /**
      * murmur hash 2.0, The murmur hash is a relatively fast hash function from http://murmurhash.googlepages.com/ for
      * platforms with efficient multiplication.
-     * 
+     *
      * @author Viliam Holub
      */
     public static long murmurhash2_64(final byte[] data, int length, int seed) {
@@ -250,13 +250,13 @@ public class Utils {
         for (int i = 0; i < length8; i++) {
             final int i8 = i * 8;
             long k = ((long) data[i8 + 0] & 0xff) //
-                     + (((long) data[i8 + 1] & 0xff) << 8) //
-                     + (((long) data[i8 + 2] & 0xff) << 16)//
-                     + (((long) data[i8 + 3] & 0xff) << 24) //
-                     + (((long) data[i8 + 4] & 0xff) << 32)//
-                     + (((long) data[i8 + 5] & 0xff) << 40)//
-                     + (((long) data[i8 + 6] & 0xff) << 48) //
-                     + (((long) data[i8 + 7] & 0xff) << 56);
+                    + (((long) data[i8 + 1] & 0xff) << 8) //
+                    + (((long) data[i8 + 2] & 0xff) << 16)//
+                    + (((long) data[i8 + 3] & 0xff) << 24) //
+                    + (((long) data[i8 + 4] & 0xff) << 32)//
+                    + (((long) data[i8 + 5] & 0xff) << 40)//
+                    + (((long) data[i8 + 6] & 0xff) << 48) //
+                    + (((long) data[i8 + 7] & 0xff) << 56);
 
             k *= m;
             k ^= k >>> r;