mysql parser bug fixed

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

@@ -0,0 +1,8 @@
+package com.alibaba.druid.sql.dialect.mysql.ast;
+
+import com.alibaba.druid.sql.ast.SQLHint;
+
+
+public interface MySqlHint extends SQLHint, MySqlObject {
+
+}

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

@@ -0,0 +1,16 @@
+package com.alibaba.druid.sql.dialect.mysql.ast;
+
+public interface MySqlIndexHint extends MySqlHint {
+    public static enum Option {
+        JOIN("JOIN"),
+        ORDER_BY("ORDER BY"),
+        GROUP_BY("GROUP BY")
+        ;
+        
+        public final String name;
+        
+        Option(String name) {
+            this.name = name;
+        }
+    }
+}

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

@@ -0,0 +1,36 @@
+package com.alibaba.druid.sql.dialect.mysql.ast;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+
+public abstract class MySqlIndexHintImpl extends MySqlObjectImpl implements MySqlIndexHint {
+
+    private static final long     serialVersionUID = 1L;
+
+    private MySqlIndexHint.Option option;
+
+    private List<SQLName>         indexList        = new ArrayList<SQLName>();
+
+    @Override
+    public abstract void accept0(MySqlASTVisitor visitor);
+
+    public MySqlIndexHint.Option getOption() {
+        return option;
+    }
+
+    public void setOption(MySqlIndexHint.Option option) {
+        this.option = option;
+    }
+
+    public List<SQLName> getIndexList() {
+        return indexList;
+    }
+
+    public void setIndexList(List<SQLName> indexList) {
+        this.indexList = indexList;
+    }
+
+}

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

@@ -0,0 +1,17 @@
+package com.alibaba.druid.sql.dialect.mysql.ast;
+
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+
+public class MySqlUseIndexHint extends MySqlIndexHintImpl {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public void accept0(MySqlASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, getIndexList());
+        }
+        visitor.endVisit(this);
+    }
+
+}

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

@@ -0,0 +1,41 @@
+package com.alibaba.druid.sql.dialect.mysql.ast.statement;
+
+import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class MySqlUnionQuery extends SQLUnionQuery implements MySqlStatement {
+
+    private static final long serialVersionUID = 1L;
+
+    private Limit             limit;
+
+    public Limit getLimit() {
+        return limit;
+    }
+
+    public void setLimit(Limit limit) {
+        this.limit = limit;
+    }
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor instanceof MySqlASTVisitor) {
+            accept0((MySqlASTVisitor) visitor);
+        } else {
+            throw new IllegalArgumentException("not support visitor type : " + visitor.getClass().getName());
+        }
+    }
+
+    @Override
+    public void accept0(MySqlASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, getLeft());
+            acceptChild(visitor, getRight());
+            acceptChild(visitor, getOrderBy());
+            acceptChild(visitor, getLimit());
+        }
+        visitor.endVisit(this);
+    }
+}

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java

@@ -38,6 +38,8 @@ import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlMatchAgainstExpr.Search
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlOutFileExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlUserName;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSQLColumnDefinition;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
 import com.alibaba.druid.sql.parser.Lexer;
 import com.alibaba.druid.sql.parser.ParserException;
 import com.alibaba.druid.sql.parser.SQLExprParser;
@@ -580,4 +582,28 @@ public class MySqlExprParser extends SQLExprParser {
         }
         return super.nameRest(name);
     }
+    
+    public Limit parseLimit() {
+        if (lexer.token() == Token.LIMIT) {
+            lexer.nextToken();
+
+            MySqlSelectQueryBlock.Limit limit = new MySqlSelectQueryBlock.Limit();
+
+            SQLExpr temp = this.expr();
+            if (lexer.token() == (Token.COMMA)) {
+                limit.setOffset(temp);
+                lexer.nextToken();
+                limit.setRowCount(this.expr());
+            } else if (identifierEquals("OFFSET")) {
+                limit.setRowCount(temp);
+                lexer.nextToken();
+                limit.setOffset(this.expr());
+            } else {
+                limit.setRowCount(temp);
+            }
+            return limit;
+        }
+
+        return null;
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlSelectParser.java

@@ -22,9 +22,14 @@ import com.alibaba.druid.sql.ast.statement.SQLSelectGroupByClause;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlIndexHint;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlUseIndexHint;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlOutFileExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectGroupBy;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.parser.Lexer;
 import com.alibaba.druid.sql.parser.ParserException;
 import com.alibaba.druid.sql.parser.SQLSelectParser;
@@ -177,24 +182,7 @@ public class MySqlSelectParser extends SQLSelectParser {
         queryBlock.setOrderBy(this.createExprParser().parseOrderBy());
 
         if (lexer.token() == Token.LIMIT) {
-            lexer.nextToken();
-
-            MySqlSelectQueryBlock.Limit limit = new MySqlSelectQueryBlock.Limit();
-
-            SQLExpr temp = this.createExprParser().expr();
-            if (lexer.token() == (Token.COMMA)) {
-                limit.setOffset(temp);
-                lexer.nextToken();
-                limit.setRowCount(createExprParser().expr());
-            } else if (identifierEquals("OFFSET")) {
-                limit.setRowCount(temp);
-                lexer.nextToken();
-                limit.setOffset(createExprParser().expr());
-            } else {
-                limit.setRowCount(temp);
-            }
-
-            queryBlock.setLimit(limit);
+            queryBlock.setLimit(parseLimit());
         }
 
         if (identifierEquals("PROCEDURE")) {
@@ -263,13 +251,64 @@ public class MySqlSelectParser extends SQLSelectParser {
     protected MySqlExprParser createExprParser() {
         return new MySqlExprParser(lexer);
     }
-    
+
     protected SQLTableSource parseTableSourceRest(SQLTableSource tableSource) throws ParserException {
         if (identifierEquals("USING")) {
             return tableSource;
         }
-        
+
+        if (identifierEquals("USE")) {
+            lexer.nextToken();
+            MySqlUseIndexHint hint = new MySqlUseIndexHint();
+            if (lexer.token() == Token.INDEX) {
+                lexer.nextToken();
+            } else {
+                accept(Token.KEY);
+            }
+            
+            if (lexer.token() == Token.FOR) {
+                lexer.nextToken();
+                
+                if (lexer.token() == Token.JOIN) {
+                    lexer.nextToken();
+                    hint.setOption(MySqlIndexHint.Option.JOIN);
+                } else if (lexer.token() == Token.ORDER) {
+                    lexer.nextToken();
+                    accept(Token.BY);
+                    hint.setOption(MySqlIndexHint.Option.ORDER_BY);
+                } else {
+                    accept(Token.GROUP);
+                    accept(Token.BY);
+                    hint.setOption(MySqlIndexHint.Option.GROUP_BY);
+                }
+            }
+            
+            accept(Token.LPAREN);
+            this.createExprParser().names(hint.getIndexList());
+            accept(Token.RPAREN);
+            tableSource.getHints().add(hint);
+        }
+
+        if (identifierEquals("IGNORE")) {
+            throw new ParserException("TODO");
+        }
+
         return super.parseTableSourceRest(tableSource);
     }
- 
+
+    protected MySqlUnionQuery createSQLUnionQuery() {
+        return new MySqlUnionQuery();
+    }
+
+    public SQLUnionQuery unionRest(SQLUnionQuery union) {
+        if (lexer.token() == Token.LIMIT) {
+            MySqlUnionQuery mysqlUnionQuery = (MySqlUnionQuery) union;
+            mysqlUnionQuery.setLimit(parseLimit());
+        }
+        return super.unionRest(union);
+    }
+
+    public Limit parseLimit() {
+        return this.createExprParser().parseLimit();
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlStatementParser.java

@@ -59,7 +59,6 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRenameTableStateme
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlReplicateStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlResetStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRollbackStatement;
-import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetCharSetStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetNamesStatement;
@@ -1930,28 +1929,8 @@ public class MySqlStatementParser extends SQLStatementParser {
         }
     }
 
-    private Limit parseLimit() {
-        if (lexer.token() == Token.LIMIT) {
-            lexer.nextToken();
-
-            MySqlSelectQueryBlock.Limit limit = new MySqlSelectQueryBlock.Limit();
-
-            SQLExpr temp = this.exprParser.expr();
-            if (lexer.token() == (Token.COMMA)) {
-                limit.setOffset(temp);
-                lexer.nextToken();
-                limit.setRowCount(exprParser.expr());
-            } else if (identifierEquals("OFFSET")) {
-                limit.setRowCount(temp);
-                lexer.nextToken();
-                limit.setOffset(exprParser.expr());
-            } else {
-                limit.setRowCount(temp);
-            }
-            return limit;
-        }
-
-        return null;
+    public Limit parseLimit() {
+        return ((MySqlExprParser) this.exprParser).parseLimit();
     }
 
     public SQLStatement parseAlter() {

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

@@ -17,6 +17,7 @@ package com.alibaba.druid.sql.dialect.mysql.visitor;
 
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlKey;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlPrimaryKey;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlUseIndexHint;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlExtractExpr;
@@ -97,6 +98,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowVariantsStatem
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowWarningsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlStartTransactionStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlTableIndex;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUpdateStatement;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
@@ -445,4 +447,12 @@ public interface MySqlASTVisitor extends SQLASTVisitor {
     boolean visit(MySqlDropViewStatement x);
     
     void endVisit(MySqlDropViewStatement x);
+    
+    boolean visit(MySqlUnionQuery x);
+    
+    void endVisit(MySqlUnionQuery x);
+    
+    boolean visit(MySqlUseIndexHint x);
+    
+    void endVisit(MySqlUseIndexHint x);
 }

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

@@ -2,6 +2,7 @@ package com.alibaba.druid.sql.dialect.mysql.visitor;
 
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlKey;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlPrimaryKey;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlUseIndexHint;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlExtractExpr;
@@ -84,6 +85,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowVariantsStatem
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowWarningsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlStartTransactionStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlTableIndex;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUpdateStatement;
 import com.alibaba.druid.sql.visitor.SQLASTVisitorAdapter;
 
@@ -969,4 +971,24 @@ public class MySqlASTVisitorAdapter extends SQLASTVisitorAdapter implements
     public void endVisit(MySqlDropViewStatement x) {
         
     }
+
+    @Override
+    public boolean visit(MySqlUnionQuery x) {
+        return true;
+    }
+
+    @Override
+    public void endVisit(MySqlUnionQuery x) {
+        
+    }
+
+    @Override
+    public boolean visit(MySqlUseIndexHint x) {
+        return true;
+    }
+
+    @Override
+    public void endVisit(MySqlUseIndexHint x) {
+        
+    }
 }

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

@@ -29,10 +29,12 @@ import com.alibaba.druid.sql.ast.statement.SQLCharactorDataType;
 import com.alibaba.druid.sql.ast.statement.SQLColumnConstraint;
 import com.alibaba.druid.sql.ast.statement.SQLColumnDefinition;
 import com.alibaba.druid.sql.ast.statement.SQLCreateTableStatement;
+import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlKey;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlPrimaryKey;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlUseIndexHint;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlCharExpr;
@@ -118,6 +120,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowVariantsStatem
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowWarningsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlStartTransactionStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlTableIndex;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUpdateStatement;
 import com.alibaba.druid.sql.visitor.SQLASTOutputVisitor;
 
@@ -161,6 +164,10 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         if (x.isHignPriority()) {
             print("HIGH_PRIORITY ");
         }
+        
+        if (x.isStraightJoin()) {
+            print("STRAIGHT_JOIN ");
+        }
 
         if (x.isSmallResult()) {
             print("SQL_SMALL_RESULT ");
@@ -1350,7 +1357,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
     @Override
     public boolean visit(MySqlDropTableStatement x) {
         if (x.isTemporary()) {
-            print("DROP TEMPORARY TABLE ");    
+            print("DROP TEMPORARY TABLE ");
         } else {
             print("DROP TABLE ");
         }
@@ -1359,14 +1366,14 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         }
 
         printAndAccept(x.getTableSources(), ", ");
-        
+
         if (x.getOption() != null) {
             print(' ');
             print(x.getOption());
         }
         return false;
     }
-    
+
     @Override
     public void endVisit(MySqlPartitionByKey x) {
 
@@ -2221,16 +2228,16 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             print(x.getType());
             print(" ");
         }
-        
+
         print("INDEX ");
-        
+
         x.getName().accept(this);
         print(" ON ");
         x.getTable().accept(this);
         print(" (");
         printAndAccept(x.getItems(), ", ");
         print(")");
-        
+
         if (x.getUsing() != null) {
             print(" USING ");
             print(x.getUsing());
@@ -2240,7 +2247,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlCreateIndexStatement x) {
-        
+
     }
 
     @Override
@@ -2253,7 +2260,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlRenameTableStatement.Item x) {
-        
+
     }
 
     @Override
@@ -2265,7 +2272,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlRenameTableStatement x) {
-        
+
     }
 
     @Override
@@ -2274,9 +2281,9 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         if (x.isIfExists()) {
             print("IF EXISTS ");
         }
-        
+
         printAndAccept(x.getTableSources(), ", ");
-        
+
         if (x.getOption() != null) {
             print(' ');
             print(x.getOption());
@@ -2286,7 +2293,100 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlDropViewStatement x) {
+
+    }
+
+    @Override
+    public boolean visit(MySqlUnionQuery x) {
+        {
+            boolean needParen = false;
+            if (x.getLeft() instanceof MySqlSelectQueryBlock) {
+                MySqlSelectQueryBlock right = (MySqlSelectQueryBlock) x.getLeft();
+                if (right.getOrderBy() != null || right.getLimit() != null) {
+                    needParen = true;
+                }
+            }
+            if (needParen) {
+                print('(');
+                x.getLeft().accept(this);
+                print(')');
+            } else {
+                x.getLeft().accept(this);
+            }
+        }
+        println();
+        print(x.getOperator().name);
+        println();
+
+        boolean needParen = false;
+
+        if (x.getOrderBy() != null || x.getLimit() != null) {
+            needParen = true;
+        } else if (x.getRight() instanceof MySqlSelectQueryBlock) {
+            MySqlSelectQueryBlock right = (MySqlSelectQueryBlock) x.getRight();
+            if (right.getOrderBy() != null || right.getLimit() != null) {
+                needParen = true;
+            }
+        }
+
+        if (needParen) {
+            print('(');
+            x.getRight().accept(this);
+            print(')');
+        } else {
+            x.getRight().accept(this);
+        }
+
+        if (x.getOrderBy() != null) {
+            println();
+            x.getOrderBy().accept(this);
+        }
+
+        if (x.getLimit() != null) {
+            println();
+            x.getLimit().accept(this);
+        }
+
+        return false;
+    }
+
+    @Override
+    public void endVisit(MySqlUnionQuery x) {
+
+    }
+
+    @Override
+    public boolean visit(MySqlUseIndexHint x) {
+        print("USE INDEX ");
+        if (x.getOption() != null) {
+            print("FOR ");
+            print(x.getOption().name);
+            print(' ');
+        }
+        print('(');
+        printAndAccept(x.getIndexList(), ", ");
+        print(')');
+        return false;
+    }
+
+    @Override
+    public void endVisit(MySqlUseIndexHint x) {
         
     }
 
+    public boolean visit(SQLExprTableSource x) {
+        x.getExpr().accept(this);
+
+        if (x.getAlias() != null) {
+            print(' ');
+            print(x.getAlias());
+        }
+        
+        for (int i = 0; i < x.getHints().size(); ++i) {
+            print(' ');
+            x.getHints().get(i).accept(this);
+        }
+
+        return false;
+    }
 }

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

@@ -8,9 +8,11 @@ import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlKey;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlPrimaryKey;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlUseIndexHint;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlExtractExpr;
@@ -93,6 +95,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowVariantsStatem
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowWarningsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlStartTransactionStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlTableIndex;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUpdateStatement;
 import com.alibaba.druid.sql.visitor.SchemaStatVisitor;
 import com.alibaba.druid.stat.TableStat;
@@ -1032,4 +1035,24 @@ public class MySqlSchemaStatVisitor extends SchemaStatVisitor implements MySqlAS
     public void endVisit(MySqlDropViewStatement x) {
         
     }
+
+    @Override
+    public boolean visit(MySqlUnionQuery x) {
+        return visit((SQLUnionQuery) x);
+    }
+
+    @Override
+    public void endVisit(MySqlUnionQuery x) {
+        
+    }
+
+    @Override
+    public boolean visit(MySqlUseIndexHint x) {
+        return false;
+    }
+
+    @Override
+    public void endVisit(MySqlUseIndexHint x) {
+        
+    }
 }

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

@@ -15,9 +15,10 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast;
 
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 
-public class OracleHint extends OracleSQLObjectImpl {
+public class OracleHint extends OracleSQLObjectImpl implements SQLHint {
 
     private static final long serialVersionUID = 1L;
 

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

@@ -18,8 +18,8 @@ package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.statement.SQLDeleteStatement;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleReturningClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -30,7 +30,7 @@ public class OracleDeleteStatement extends SQLDeleteStatement {
 
     private boolean                only             = false;
     
-    private final List<OracleHint> hints            = new ArrayList<OracleHint>();
+    private final List<SQLHint> hints            = new ArrayList<SQLHint>();
     private OracleReturningClause  returning        = null;
 
     public OracleDeleteStatement(){
@@ -45,7 +45,7 @@ public class OracleDeleteStatement extends SQLDeleteStatement {
         this.returning = returning;
     }
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return this.hints;
     }
 

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

@@ -3,8 +3,8 @@ package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleErrorLoggingClause;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleReturningClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
@@ -16,13 +16,13 @@ public class OracleInsertStatement extends SQLInsertStatement implements OracleS
 
     private OracleReturningClause    returning;
     private OracleErrorLoggingClause errorLogging;
-    private List<OracleHint>         hints            = new ArrayList<OracleHint>();
+    private List<SQLHint>            hints            = new ArrayList<SQLHint>();
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return hints;
     }
 
-    public void setHints(List<OracleHint> hints) {
+    public void setHints(List<SQLHint> hints) {
         this.hints = hints;
     }
 

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

@@ -4,10 +4,10 @@ import java.util.ArrayList;
 import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.OracleSQLObjectImpl;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleErrorLoggingClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
@@ -16,7 +16,7 @@ public class OracleMergeStatement extends OracleStatementImpl {
 
     private static final long      serialVersionUID = 1L;
 
-    private final List<OracleHint> hints            = new ArrayList<OracleHint>();
+    private final List<SQLHint> hints            = new ArrayList<SQLHint>();
 
     private SQLName                into;
     private String                 alias;
@@ -94,7 +94,7 @@ public class OracleMergeStatement extends OracleStatementImpl {
         this.errorLoggingClause = errorLoggingClause;
     }
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return hints;
     }
 

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

@@ -4,9 +4,9 @@ import java.util.ArrayList;
 import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.statement.SQLInsertInto;
 import com.alibaba.druid.sql.ast.statement.SQLSelect;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.OracleSQLObject;
 import com.alibaba.druid.sql.dialect.oracle.ast.OracleSQLObjectImpl;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleErrorLoggingClause;
@@ -25,13 +25,13 @@ public class OracleMultiInsertStatement extends OracleStatementImpl {
     private SQLSelect         subQuery;
     private Option            option;
     private List<Entry>       entries          = new ArrayList<Entry>();
-    private List<OracleHint>  hints            = new ArrayList<OracleHint>();
+    private List<SQLHint>     hints            = new ArrayList<SQLHint>(1);
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return hints;
     }
 
-    public void setHints(List<OracleHint> hints) {
+    public void setHints(List<SQLHint> hints) {
         this.hints = hints;
     }
 

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

@@ -20,7 +20,6 @@ import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.statement.SQLJoinTableSource;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.FlashbackQueryClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -32,7 +31,6 @@ public class OracleSelectJoin extends SQLJoinTableSource implements OracleSelect
     private final List<SQLExpr>     using            = new ArrayList<SQLExpr>();
     protected OracleSelectPivotBase pivot;
     protected FlashbackQueryClause  flashback;
-    private List<OracleHint>        hints            = new ArrayList<OracleHint>();
 
     public OracleSelectJoin(String alias){
         super(alias);
@@ -42,14 +40,6 @@ public class OracleSelectJoin extends SQLJoinTableSource implements OracleSelect
 
     }
 
-    public List<OracleHint> getHints() {
-        return hints;
-    }
-
-    public void setHints(List<OracleHint> hints) {
-        this.hints = hints;
-    }
-
     public FlashbackQueryClause getFlashback() {
         return flashback;
     }

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

@@ -18,10 +18,10 @@ package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.ModelClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -30,7 +30,7 @@ public class OracleSelectQueryBlock extends SQLSelectQueryBlock {
 
     private static final long                  serialVersionUID = 1L;
 
-    private final List<OracleHint>             hints            = new ArrayList<OracleHint>(1);
+    private final List<SQLHint>                hints            = new ArrayList<SQLHint>(1);
 
     private OracleSelectHierachicalQueryClause hierachicalQueryClause;
     private ModelClause                        modelClause;
@@ -55,7 +55,7 @@ public class OracleSelectQueryBlock extends SQLSelectQueryBlock {
         this.hierachicalQueryClause = hierachicalQueryClause;
     }
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return this.hints;
     }
 

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

@@ -15,12 +15,8 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 
-import java.util.ArrayList;
-import java.util.List;
-
 import com.alibaba.druid.sql.ast.statement.SQLSelect;
 import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.FlashbackQueryClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -33,18 +29,7 @@ public class OracleSelectSubqueryTableSource extends SQLSubqueryTableSource impl
 
     protected FlashbackQueryClause  flashback;
 
-    private List<OracleHint>        hints            = new ArrayList<OracleHint>();
-
     public OracleSelectSubqueryTableSource(){
-
-    }
-
-    public List<OracleHint> getHints() {
-        return hints;
-    }
-
-    public void setHints(List<OracleHint> hints) {
-        this.hints = hints;
     }
 
     public FlashbackQueryClause getFlashback() {
@@ -82,7 +67,7 @@ public class OracleSelectSubqueryTableSource extends SQLSubqueryTableSource impl
 
     protected void accept0(OracleASTVisitor visitor) {
         if (visitor.visit(this)) {
-            acceptChild(visitor, this.hints);
+            acceptChild(visitor, this.getHints());
             acceptChild(visitor, this.select);
             acceptChild(visitor, this.pivot);
             acceptChild(visitor, this.flashback);

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

@@ -15,11 +15,7 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 
-import java.util.ArrayList;
-import java.util.List;
-
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.FlashbackQueryClause;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.PartitionExtensionClause;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.SampleClause;
@@ -37,20 +33,11 @@ public class OracleSelectTableReference extends SQLExprTableSource implements Or
     protected SampleClause             sampleClause;
 
     protected FlashbackQueryClause     flashback;
-    private List<OracleHint>           hints            = new ArrayList<OracleHint>();
 
     public OracleSelectTableReference(){
 
     }
 
-    public List<OracleHint> getHints() {
-        return hints;
-    }
-
-    public void setHints(List<OracleHint> hints) {
-        this.hints = hints;
-    }
-
     public FlashbackQueryClause getFlashback() {
         return flashback;
     }

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

@@ -15,10 +15,7 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 
-import java.util.List;
-
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.FlashbackQueryClause;
 
 public interface OracleSelectTableSource extends SQLTableSource {
@@ -30,6 +27,4 @@ public interface OracleSelectTableSource extends SQLTableSource {
     FlashbackQueryClause getFlashback();
 
     void setFlashback(FlashbackQueryClause flashback);
-    
-    List<OracleHint> getHints();
 }

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

@@ -19,22 +19,22 @@ import java.util.ArrayList;
 import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class OracleUpdateStatement extends SQLUpdateStatement implements OracleStatement {
 
-    private static final long      serialVersionUID = 1L;
+    private static final long   serialVersionUID = 1L;
 
-    private final List<OracleHint> hints            = new ArrayList<OracleHint>(1);
-    private boolean                only             = false;
-    private String                 alias;
-    private SQLExpr                where;
+    private final List<SQLHint> hints            = new ArrayList<SQLHint>(1);
+    private boolean             only             = false;
+    private String              alias;
+    private SQLExpr             where;
 
-    private List<SQLExpr>          returning        = new ArrayList<SQLExpr>();
-    private List<SQLExpr>          returningInto    = new ArrayList<SQLExpr>();
+    private List<SQLExpr>       returning        = new ArrayList<SQLExpr>();
+    private List<SQLExpr>       returningInto    = new ArrayList<SQLExpr>();
 
     public OracleUpdateStatement(){
 
@@ -103,7 +103,7 @@ public class OracleUpdateStatement extends SQLUpdateStatement implements OracleS
         this.only = only;
     }
 
-    public List<OracleHint> getHints() {
+    public List<SQLHint> getHints() {
         return this.hints;
     }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleExprParser.java

@@ -21,6 +21,7 @@ import java.util.List;
 import com.alibaba.druid.sql.ast.SQLDataType;
 import com.alibaba.druid.sql.ast.SQLDataTypeImpl;
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLOrderingSpecification;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
@@ -747,7 +748,7 @@ public class OracleExprParser extends SQLExprParser {
         return super.relationalRest(expr);
     }
     
-    public void parseHints(List<OracleHint> hints) {
+    public void parseHints(List<SQLHint> hints) {
         if (lexer.token() == Token.HINT) {
             hints.add(new OracleHint(lexer.stringVal()));
             lexer.nextToken();

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleSelectParser.java

@@ -286,6 +286,9 @@ public class OracleSelectParser extends SQLSelectParser {
             if (lexer.token() == (Token.ALL)) {
                 union.setOperator(SQLUnionOperator.UNION_ALL);
                 lexer.nextToken();
+            } else if (lexer.token() == (Token.DISTINCT)) {
+                union.setOperator(SQLUnionOperator.DISTINCT);
+                lexer.nextToken();
             }
 
             SQLSelectQuery right = query();

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java

@@ -20,6 +20,7 @@ import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLDataTypeImpl;
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
@@ -39,7 +40,6 @@ import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
-import com.alibaba.druid.sql.dialect.oracle.ast.OracleHint;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleErrorLoggingClause;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleParameter;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.OracleReturningClause;
@@ -115,7 +115,7 @@ public class OracleStatementParser extends SQLStatementParser {
         return (OracleExprParser) exprParser;
     }
     
-    public void parseHints(List<OracleHint> hints) {
+    public void parseHints(List<SQLHint> hints) {
         this.getExprParser().parseHints(hints);
     }
 
@@ -128,7 +128,7 @@ public class OracleStatementParser extends SQLStatementParser {
             OracleInsertStatement stmt = (OracleInsertStatement) insertStatement;
             this.getExprParser().parseHints(stmt.getHints());
         } else {
-            List<OracleHint> hints = new ArrayList<OracleHint>();
+            List<SQLHint> hints = new ArrayList<SQLHint>(1);
             this.getExprParser().parseHints(hints);
         }
     }
@@ -1243,7 +1243,7 @@ public class OracleStatementParser extends SQLStatementParser {
         
         accept(Token.INSERT);
 
-        List<OracleHint> hints = new ArrayList<OracleHint>();
+        List<SQLHint> hints = new ArrayList<SQLHint>();
 
         parseHints(hints);
 

src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleOutputVisitor.java

@@ -19,6 +19,7 @@ import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLDataType;
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLHint;
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLObject;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
@@ -200,7 +201,7 @@ public class OracleOutputVisitor extends SQLASTOutputVisitor implements OracleAS
         }
     }
 
-    private void printHints(List<OracleHint> hints) {
+    private void printHints(List<SQLHint> hints) {
         if (hints.size() > 0) {
             print("/*+ ");
             printAndAccept(hints, ", ");