improved sql parser. bug fixed for issue #2446

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

@@ -56,6 +56,7 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
     protected String                     cachedSelectList; // optimized for SelectListCache
     protected long                       cachedSelectListHash; // optimized for SelectListCache
 
+    protected List<SQLCommentHint>       hints;
     protected String                     dbType;
 
     public SQLSelectQueryBlock(){
@@ -322,6 +323,16 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         return sortBy;
     }
 
+    public void addSortBy(SQLSelectOrderByItem item) {
+        if (sortBy == null) {
+            sortBy = new ArrayList<SQLSelectOrderByItem>();
+        }
+        if (item != null) {
+            item.setParent(this);
+        }
+        this.sortBy.add(item);
+    }
+
 	@Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
@@ -333,6 +344,8 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
             acceptChild(visitor, this.connectBy);
             acceptChild(visitor, this.groupBy);
             acceptChild(visitor, this.orderBy);
+            acceptChild(visitor, this.distributeBy);
+            acceptChild(visitor, this.sortBy);
             acceptChild(visitor, this.waitTime);
             acceptChild(visitor, this.limit);
         }
@@ -676,6 +689,29 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         return cachedSelectListHash;
     }
 
+    public List<SQLCommentHint> getHintsDirect() {
+        return hints;
+    }
+
+    public List<SQLCommentHint> getHints() {
+        if (hints == null) {
+            hints = new ArrayList<SQLCommentHint>(2);
+        }
+        return hints;
+    }
+
+    public void setHints(List<SQLCommentHint> hints) {
+        this.hints = hints;
+    }
+
+    public int getHintsSize() {
+        if (hints == null) {
+            return 0;
+        }
+
+        return hints.size();
+    }
+
     public String getDbType() {
         return dbType;
     }

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

@@ -0,0 +1,83 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.sql.ast.statement;
+
+import com.alibaba.druid.sql.ast.SQLHint;
+import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.ast.expr.SQLListExpr;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by wenshao on 23/02/2017.
+ */
+public class SQLValuesTableSource extends SQLTableSourceImpl {
+    private List<SQLListExpr> values = new ArrayList<SQLListExpr>();
+    private List<SQLName> columns = new ArrayList<SQLName>();
+
+    public List<SQLListExpr> getValues() {
+        return values;
+    }
+
+    public List<SQLName> getColumns() {
+        return columns;
+    }
+
+    @Override
+    public void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, values);
+            acceptChild(visitor, columns);
+        }
+        visitor.endVisit(this);
+    }
+
+    @Override
+    public SQLValuesTableSource clone() {
+
+        SQLValuesTableSource x = new SQLValuesTableSource();
+
+        x.setAlias(this.alias);
+
+        for (SQLListExpr e : this.values) {
+            SQLListExpr e2 = e.clone();
+            e2.setParent(x);
+            x.getValues().add(e2);
+        }
+
+        for (SQLName e : this.columns) {
+            SQLName e2 = e.clone();
+            e2.setParent(x);
+            x.getColumns().add(e2);
+        }
+
+        if (this.flashback != null) {
+            x.setFlashback(this.flashback.clone());
+        }
+
+        if (this.hints != null) {
+            for (SQLHint e : this.hints) {
+                SQLHint e2 = e.clone();
+                e2.setParent(x);
+                x.getHints().add(e2);
+            }
+        }
+
+        return x;
+    }
+}

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2SelectParser.java

@@ -16,6 +16,7 @@
 package com.alibaba.druid.sql.dialect.db2.parser;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLObject;
 import com.alibaba.druid.sql.ast.SQLOrderBy;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
@@ -45,14 +46,14 @@ public class DB2SelectParser extends SQLSelectParser {
     }
 
     @Override
-    public SQLSelectQuery query() {
+    public SQLSelectQuery query(SQLObject parent, boolean acceptUnion) {
         if (lexer.token() == Token.LPAREN) {
             lexer.nextToken();
 
             SQLSelectQuery select = query();
             accept(Token.RPAREN);
 
-            return queryRest(select);
+            return queryRest(select, acceptUnion);
         }
 
         accept(Token.SELECT);
@@ -83,7 +84,7 @@ public class DB2SelectParser extends SQLSelectParser {
         parseHierachical(queryBlock);
 
         parseGroupBy(queryBlock);
-        
+
         if (lexer.token() == Token.ORDER) {
             SQLOrderBy orderBy = parseOrderBy();
             queryBlock.setOrderBy(orderBy);
@@ -102,7 +103,7 @@ public class DB2SelectParser extends SQLSelectParser {
                 accept(Token.ONLY);
                 continue;
             }
-            
+
             if (lexer.token() == Token.WITH) {
                 lexer.nextToken();
                 if (lexer.identifierEquals("RR")) {
@@ -119,10 +120,10 @@ public class DB2SelectParser extends SQLSelectParser {
                 lexer.nextToken();
                 continue;
             }
-            
+
             if (lexer.token() == Token.FOR) {
                 lexer.nextToken();
-                
+
                 if (lexer.token() == Token.UPDATE) {
                     queryBlock.setForUpdate(true);
                     lexer.nextToken();
@@ -132,11 +133,11 @@ public class DB2SelectParser extends SQLSelectParser {
                     queryBlock.setForReadOnly(true);
                 }
             }
-            
+
             if (lexer.token() == Token.OPTIMIZE) {
                 lexer.nextToken();
                 accept(Token.FOR);
-                
+
                 queryBlock.setOptimizeFor(this.expr());
                 if (lexer.identifierEquals("ROW")) {
                     lexer.nextToken();
@@ -144,10 +145,10 @@ public class DB2SelectParser extends SQLSelectParser {
                     acceptIdentifier("ROWS");
                 }
             }
-            
+
             break;
         }
 
-        return queryRest(queryBlock);
+        return queryRest(queryBlock, acceptUnion);
     }
 }

src/main/java/com/alibaba/druid/sql/dialect/hive/parser/HiveSelectParser.java

@@ -15,7 +15,9 @@
  */
 package com.alibaba.druid.sql.dialect.hive.parser;
 
+import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLOrderBy;
+import com.alibaba.druid.sql.ast.SQLOrderingSpecification;
 import com.alibaba.druid.sql.ast.statement.*;
 import com.alibaba.druid.sql.parser.SQLExprParser;
 import com.alibaba.druid.sql.parser.SQLSelectListCache;
@@ -40,4 +42,32 @@ public class HiveSelectParser extends SQLSelectParser {
         return new HiveExprParser(lexer);
     }
 
+    protected void parseSortBy(SQLSelectQueryBlock queryBlock) {
+        if (lexer.token() == Token.SORT) {
+            lexer.nextToken();
+            accept(Token.BY);
+            for (;;) {
+                SQLExpr expr = this.expr();
+
+                SQLSelectOrderByItem sortByItem = new SQLSelectOrderByItem(expr);
+
+                if (lexer.token() == Token.ASC) {
+                    sortByItem.setType(SQLOrderingSpecification.ASC);
+                    lexer.nextToken();
+                } else if (lexer.token() == Token.DESC) {
+                    sortByItem.setType(SQLOrderingSpecification.DESC);
+                    lexer.nextToken();
+                }
+
+                queryBlock.addSortBy(sortByItem);
+
+                if (lexer.token() == Token.COMMA) {
+                    lexer.nextToken();
+                } else {
+                    break;
+                }
+            }
+        }
+    }
+
 }

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

@@ -39,7 +39,6 @@ public class MySqlSelectQueryBlock extends SQLSelectQueryBlock implements MySqlO
     private SQLName              procedureName;
     private List<SQLExpr>        procedureArgumentList;
     private boolean              lockInShareMode;
-    private List<SQLCommentHint> hints;
     private SQLName              forcePartition; // for petadata
 
     public MySqlSelectQueryBlock(){
@@ -74,25 +73,6 @@ public class MySqlSelectQueryBlock extends SQLSelectQueryBlock implements MySqlO
         return x;
     }
 
-    public int getHintsSize() {
-        if (hints == null) {
-            return 0;
-        }
-
-        return hints.size();
-    }
-
-    public List<SQLCommentHint> getHints() {
-        if (hints == null) {
-            hints = new ArrayList<SQLCommentHint>(2);
-        }
-        return hints;
-    }
-
-    public void setHints(List<SQLCommentHint> hints) {
-        this.hints = hints;
-    }
-
     public boolean isLockInShareMode() {
         return lockInShareMode;
     }

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

@@ -17,6 +17,7 @@ package com.alibaba.druid.sql.dialect.mysql.parser;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.ast.SQLObject;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLListExpr;
@@ -75,9 +76,9 @@ public class MySqlSelectParser extends SQLSelectParser {
         queryBlock.setFrom(parseTableSource());
     }
 
-  
+
     @Override
-    public SQLSelectQuery query() {
+    public SQLSelectQuery query(SQLObject parent, boolean acceptUnion) {
         if (lexer.token() == Token.LPAREN) {
             lexer.nextToken();
 
@@ -85,10 +86,11 @@ public class MySqlSelectParser extends SQLSelectParser {
             select.setBracket(true);
             accept(Token.RPAREN);
 
-            return queryRest(select);
+            return queryRest(select, acceptUnion);
         }
 
         MySqlSelectQueryBlock queryBlock = new MySqlSelectQueryBlock();
+        queryBlock.setParent(parent);
 
         if (lexer.hasComment() && lexer.isKeepComments()) {
             queryBlock.addBeforeComment(lexer.readAndResetComments());
@@ -103,8 +105,12 @@ public class MySqlSelectParser extends SQLSelectParser {
         if (lexer.token() == Token.SELECT) {
             lexer.nextTokenValue();
 
-            if (lexer.token() == Token.HINT) {
-                this.exprParser.parseHints(queryBlock.getHints());
+            for(;;) {
+                if (lexer.token() == Token.HINT) {
+                    this.exprParser.parseHints(queryBlock.getHints());
+                } else {
+                    break;
+                }
             }
 
             Token token = lexer.token();
@@ -167,7 +173,7 @@ public class MySqlSelectParser extends SQLSelectParser {
                 SQLName partition = this.exprParser.name();
                 queryBlock.setForcePartition(partition);
             }
-            
+
             parseInto(queryBlock);
         }
 
@@ -197,7 +203,7 @@ public class MySqlSelectParser extends SQLSelectParser {
             accept(Token.UPDATE);
 
             queryBlock.setForUpdate(true);
-            
+
             if (lexer.identifierEquals(FnvHash.Constants.NO_WAIT) || lexer.identifierEquals(FnvHash.Constants.NOWAIT)) {
                 lexer.nextToken();
                 queryBlock.setNoWait(true);
@@ -216,7 +222,7 @@ public class MySqlSelectParser extends SQLSelectParser {
             queryBlock.setLockInShareMode(true);
         }
 
-        return queryRest(queryBlock);
+        return queryRest(queryBlock, acceptUnion);
     }
     
     public SQLTableSource parseTableSource() {

src/main/java/com/alibaba/druid/sql/dialect/odps/ast/OdpsSelectQueryBlock.java

@@ -34,8 +34,6 @@ public class OdpsSelectQueryBlock extends SQLSelectQueryBlock {
 
     private SQLOrderBy orderBy;
 
-    protected List<SQLHint> hints;
-
     public OdpsSelectQueryBlock(){
         dbType = JdbcConstants.ODPS;
 
@@ -72,21 +70,6 @@ public class OdpsSelectQueryBlock extends SQLSelectQueryBlock {
         return true;
     }
 
-    public List<SQLHint> getHintsDirect() {
-        return hints;
-    }
-
-    public List<SQLHint> getHints() {
-        if (hints == null) {
-            hints = new ArrayList<SQLHint>(2);
-        }
-        return hints;
-    }
-
-    public void setHints(List<SQLHint> hints) {
-        this.hints = hints;
-    }
-
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor instanceof OdpsASTVisitor) {

src/main/java/com/alibaba/druid/sql/dialect/odps/visitor/OdpsOutputVisitor.java

@@ -455,7 +455,7 @@ public class OdpsOutputVisitor extends SQLASTOutputVisitor implements OdpsASTVis
 
         print0(ucase ? "SELECT " : "select ");
 
-        List<SQLHint> hints = x.getHintsDirect();
+        List<SQLCommentHint> hints = x.getHintsDirect();
         if (hints != null) {
             printAndAccept(hints, " ");
             print(' ');

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

@@ -35,11 +35,7 @@ import com.alibaba.druid.util.JdbcConstants;
 
 public class OracleSelectQueryBlock extends SQLSelectQueryBlock implements OracleSQLObject {
 
-    private List<SQLCommentHint>       hints;
-
     private ModelClause                modelClause;
-
-
     private boolean                    skipLocked  = false;
 
     public OracleSelectQueryBlock clone() {
@@ -84,21 +80,6 @@ public class OracleSelectQueryBlock extends SQLSelectQueryBlock implements Oracl
         this.modelClause = modelClause;
     }
 
-    public List<SQLCommentHint> getHints() {
-        if (hints == null) {
-            hints = new ArrayList<SQLCommentHint>(1);
-        }
-        return this.hints;
-    }
-
-    public int getHintsSize() {
-        if (hints == null) {
-            return 0;
-        }
-
-        return hints.size();
-    }
-
     public boolean isSkipLocked() {
         return skipLocked;
     }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerSelectParser.java

@@ -16,6 +16,7 @@
 package com.alibaba.druid.sql.dialect.sqlserver.parser;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLObject;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.statement.*;
 import com.alibaba.druid.sql.dialect.sqlserver.ast.SQLServerSelectQueryBlock;
@@ -115,14 +116,14 @@ public class SQLServerSelectParser extends SQLSelectParser {
         return select;
     }
 
-    public SQLSelectQuery query() {
+    public SQLSelectQuery query(SQLObject parent, boolean acceptUnion) {
         if (lexer.token() == Token.LPAREN) {
             lexer.nextToken();
 
             SQLSelectQuery select = query();
             accept(Token.RPAREN);
 
-            return queryRest(select);
+            return queryRest(select, acceptUnion);
         }
 
         SQLServerSelectQueryBlock queryBlock = new SQLServerSelectQueryBlock();
@@ -167,7 +168,7 @@ public class SQLServerSelectParser extends SQLSelectParser {
 
         parseFetchClause(queryBlock);
 
-        return queryRest(queryBlock);
+        return queryRest(queryBlock, acceptUnion);
     }
 
     protected SQLServerExprParser createExprParser() {

src/main/java/com/alibaba/druid/sql/parser/Keywords.java

@@ -160,7 +160,8 @@ public class Keywords {
         map.put("FETCH", Token.FETCH);
         map.put("OUT", Token.OUT);
         map.put("INOUT", Token.INOUT);
-        
+        map.put("LIMIT", Token.LIMIT);
+
         DEFAULT_KEYWORDS = new Keywords(map);
 
         Map<String, Token> sqlitemap = new HashMap<String, Token>();

src/main/java/com/alibaba/druid/sql/parser/SQLSelectParser.java

@@ -100,23 +100,62 @@ public class SQLSelectParser extends SQLParser {
     }
 
     public SQLSelectQuery queryRest(SQLSelectQuery selectQuery) {
+        return queryRest(selectQuery, true);
+    }
+
+    public SQLSelectQuery queryRest(SQLSelectQuery selectQuery, boolean acceptUnion) {
+        if (!acceptUnion) {
+            return selectQuery;
+        }
+
         if (lexer.token == Token.UNION) {
-            lexer.nextToken();
-
-            SQLUnionQuery union = createSQLUnionQuery();
-            union.setLeft(selectQuery);
-
-            if (lexer.token == Token.ALL) {
-                union.setOperator(SQLUnionOperator.UNION_ALL);
+            do {
                 lexer.nextToken();
-            } else if (lexer.token == Token.DISTINCT) {
-                union.setOperator(SQLUnionOperator.DISTINCT);
-                lexer.nextToken();
-            }
-            SQLSelectQuery right = this.query();
-            union.setRight(right);
 
-            return unionRest(union);
+                SQLUnionQuery union = createSQLUnionQuery();
+                if (union.getLeft() == null) {
+                    union.setLeft(selectQuery);
+                }
+
+                boolean paren = lexer.token == Token.LPAREN;
+
+                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 = this.query(paren ? null : union, false);
+                union.setRight(right);
+
+                if (!paren) {
+                    if (right instanceof SQLSelectQueryBlock) {
+                        SQLSelectQueryBlock rightQuery = (SQLSelectQueryBlock) right;
+                        SQLOrderBy orderBy = rightQuery.getOrderBy();
+                        SQLLimit limit = rightQuery.getLimit();
+                        if (orderBy != null && limit == null) {
+                            union.setOrderBy(orderBy);
+                            rightQuery.setOrderBy(null);
+                        }
+                    } else if (right instanceof SQLUnionQuery) {
+                        SQLUnionQuery rightUnion = (SQLUnionQuery) right;
+                        if (rightUnion.getOrderBy() != null) {
+                            union.setOrderBy(rightUnion.getOrderBy());
+                            rightUnion.setOrderBy(null);
+                        }
+                    }
+                }
+
+                union = unionRest(union);
+
+                selectQuery = union;
+
+            } while (lexer.token() == Token.UNION);
+
+            selectQuery = queryRest(selectQuery, true);
+
+            return selectQuery;
         }
 
         if (lexer.token == Token.EXCEPT) {
@@ -127,10 +166,10 @@ public class SQLSelectParser extends SQLParser {
 
             union.setOperator(SQLUnionOperator.EXCEPT);
 
-            SQLSelectQuery right = this.query();
+            SQLSelectQuery right = this.query(union, false);
             union.setRight(right);
 
-            return union;
+            return queryRest(union, true);
         }
 
         if (lexer.token == Token.INTERSECT) {
@@ -141,13 +180,13 @@ public class SQLSelectParser extends SQLParser {
 
             union.setOperator(SQLUnionOperator.INTERSECT);
 
-            SQLSelectQuery right = this.query();
+            SQLSelectQuery right = this.query(union, false);
             union.setRight(right);
 
-            return union;
+            return queryRest(union, true);
         }
 
-        if (lexer.token == Token.MINUS) {
+        if (acceptUnion && lexer.token == Token.MINUS) {
             lexer.nextToken();
 
             SQLUnionQuery union = new SQLUnionQuery();
@@ -155,33 +194,45 @@ public class SQLSelectParser extends SQLParser {
 
             union.setOperator(SQLUnionOperator.MINUS);
 
-            SQLSelectQuery right = this.query();
+            SQLSelectQuery right = this.query(union, false);
             union.setRight(right);
 
-            return union;
+            return queryRest(union, true);
         }
 
         return selectQuery;
     }
 
     public SQLSelectQuery query() {
+        return query(null, true);
+    }
+
+    public SQLSelectQuery query(SQLObject parent) {
+        return query(parent, true);
+    }
+
+    public SQLSelectQuery query(SQLObject parent, boolean acceptUnion) {
         if (lexer.token == Token.LPAREN) {
             lexer.nextToken();
 
             SQLSelectQuery select = query();
             accept(Token.RPAREN);
 
-            return queryRest(select);
+            return queryRest(select, acceptUnion);
         }
-        
+
         SQLSelectQueryBlock queryBlock = new SQLSelectQueryBlock();
-        
+
         if (lexer.hasComment() && lexer.isKeepComments()) {
             queryBlock.addBeforeComment(lexer.readAndResetComments());
         }
 
         accept(Token.SELECT);
 
+        if (lexer.token() == Token.HINT) {
+            this.exprParser.parseHints(queryBlock.getHints());
+        }
+
         if (lexer.token == Token.COMMENT) {
             lexer.nextToken();
         }
@@ -219,9 +270,15 @@ public class SQLSelectParser extends SQLParser {
 
         parseGroupBy(queryBlock);
 
+        parseSortBy(queryBlock);
+
         parseFetchClause(queryBlock);
 
-        return queryRest(queryBlock);
+        return queryRest(queryBlock, acceptUnion);
+    }
+
+    protected void parseSortBy(SQLSelectQueryBlock queryBlock) {
+
     }
 
     protected void withSubquery(SQLSelect select) {
@@ -533,10 +590,10 @@ public class SQLSelectParser extends SQLParser {
             lexer.nextToken();
             SQLTableSource tableSource;
             if (lexer.token == Token.SELECT || lexer.token == Token.WITH
-            		|| lexer.token == Token.SEL) {
+                    || lexer.token == Token.SEL) {
                 SQLSelect select = select();
                 accept(Token.RPAREN);
-                SQLSelectQuery query = queryRest(select.getQuery());
+                SQLSelectQuery query = queryRest(select.getQuery(), true);
                 if (query instanceof SQLUnionQuery) {
                     tableSource = new SQLUnionQueryTableSource((SQLUnionQuery) query);
                 } else {
@@ -550,9 +607,61 @@ public class SQLSelectParser extends SQLParser {
                 accept(Token.RPAREN);
             }
 
+            if (lexer.token == Token.AS
+                    && tableSource instanceof SQLValuesTableSource
+                    && ((SQLValuesTableSource) tableSource).getColumns().size() == 0)
+            {
+                lexer.nextToken();
+
+                String alias = this.tableAlias();
+                tableSource.setAlias(alias);
+
+                SQLValuesTableSource values = (SQLValuesTableSource) tableSource;
+                accept(Token.LPAREN);
+                this.exprParser.names(values.getColumns(), values);
+                accept(Token.RPAREN);
+            }
+
             return parseTableSourceRest(tableSource);
         }
 
+        if (lexer.token() == Token.VALUES) {
+            lexer.nextToken();
+            SQLValuesTableSource tableSource = new SQLValuesTableSource();
+
+            for (;;) {
+                accept(Token.LPAREN);
+                SQLListExpr listExpr = new SQLListExpr();
+                this.exprParser.exprList(listExpr.getItems(), listExpr);
+                accept(Token.RPAREN);
+
+                listExpr.setParent(tableSource);
+
+                tableSource.getValues().add(listExpr);
+
+                if (lexer.token == Token.COMMA) {
+                    lexer.nextToken();
+                    continue;
+                }
+                break;
+            }
+
+            if (lexer.token == Token.RPAREN) {
+                return tableSource;
+            }
+
+            String alias = this.tableAlias();
+            if (alias != null) {
+                tableSource.setAlias(alias);
+            }
+
+            accept(Token.LPAREN);
+            this.exprParser.names(tableSource.getColumns(), tableSource);
+            accept(Token.RPAREN);
+
+            return tableSource;
+        }
+
         if (lexer.token == Token.SELECT) {
             throw new ParserException("TODO " + lexer.info());
         }
@@ -562,11 +671,11 @@ public class SQLSelectParser extends SQLParser {
         parseTableSourceQueryTableExpr(tableReference);
 
         SQLTableSource tableSrc = parseTableSourceRest(tableReference);
-        
+
         if (lexer.hasComment() && lexer.isKeepComments()) {
             tableSrc.addAfterComment(lexer.readAndResetComments());
         }
-        
+
         return tableSrc;
     }
 

src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -2708,21 +2708,106 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
     @Override
     public boolean visit(SQLUnionQuery x) {
         SQLUnionOperator operator = x.getOperator();
+        SQLSelectQuery left = x.getLeft();
+        SQLSelectQuery right = x.getRight();
 
         boolean bracket = x.isBracket() && !(x.getParent() instanceof SQLUnionQueryTableSource);
 
+        SQLOrderBy orderBy = x.getOrderBy();
+        if ((!bracket)
+                && left instanceof SQLUnionQuery
+                && ((SQLUnionQuery) left).getOperator() == operator
+                && !right.isBracket()
+                && orderBy == null) {
+
+            SQLUnionQuery leftUnion = (SQLUnionQuery) left;
+
+            List<SQLSelectQuery> rights = new ArrayList<SQLSelectQuery>();
+            rights.add(right);
+
+            for (;;) {
+                SQLSelectQuery leftLeft = leftUnion.getLeft();
+                SQLSelectQuery leftRight = leftUnion.getRight();
+
+                if ((!leftUnion.isBracket())
+                        && leftUnion.getOrderBy() == null
+                        && (!leftLeft.isBracket())
+                        && (!leftRight.isBracket())
+                        && leftLeft instanceof SQLUnionQuery
+                        && ((SQLUnionQuery) leftLeft).getOperator() == operator) {
+                    rights.add(leftRight);
+                    leftUnion = (SQLUnionQuery) leftLeft;
+                    continue;
+                } else {
+                    rights.add(leftRight);
+                    rights.add(leftLeft);
+                }
+                break;
+            }
+
+            for (int i = rights.size() - 1; i >= 0; i--) {
+                SQLSelectQuery item = rights.get(i);
+                item.accept(this);
+
+                if (i > 0) {
+                    println();
+                    print0(ucase ? operator.name : operator.name_lcase);
+                    println();
+                }
+            }
+            return false;
+        }
+
         if (bracket) {
             print('(');
         }
-        x.getLeft().accept(this);
+
+        if (left != null) {
+            for (;;) {
+                if (left.getClass() == SQLUnionQuery.class) {
+                    SQLUnionQuery leftUnion = (SQLUnionQuery) left;
+                    SQLSelectQuery leftLeft = leftUnion.getLeft();
+                    SQLSelectQuery leftRigt = leftUnion.getRight();
+                    if ((!leftUnion.isBracket())
+                            && leftUnion.getRight() instanceof SQLSelectQueryBlock
+                            && leftUnion.getLeft() != null
+                            && leftUnion.getOrderBy() == null)
+                    {
+                        if (leftLeft.getClass() == SQLUnionQuery.class) {
+                            visit((SQLUnionQuery) leftLeft);
+                        } else {
+                            printQuery(leftLeft);
+                        }
+                        println();
+                        print0(ucase ? leftUnion.getOperator().name : leftUnion.getOperator().name_lcase);
+                        println();
+                        leftRigt.accept(this);
+                    } else {
+                        visit(leftUnion);
+                    }
+                } else {
+                    left.accept(this);
+                }
+                break;
+            }
+        }
+
+        if (right == null) {
+            return false;
+        }
 
         println();
         print0(ucase ? operator.name : operator.name_lcase);
         println();
 
-        SQLSelectQuery right = x.getRight();
-        SQLOrderBy orderBy = x.getOrderBy();
-        boolean needParen = orderBy != null && !right.isBracket();
+        boolean needParen = false;
+        if (orderBy != null
+                && (!right.isBracket()) && right instanceof SQLSelectQueryBlock) {
+            SQLSelectQueryBlock rightQuery = (SQLSelectQueryBlock) right;
+            if (rightQuery.getOrderBy() != null || rightQuery.getLimit() != null) {
+                needParen = true;
+            }
+        }
 
         if (needParen) {
             print('(');
@@ -6318,4 +6403,27 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
         printAndAccept(x.getValues(), ", ");
         return false;
     }
+
+    @Override
+    public boolean visit(SQLValuesTableSource x) {
+        List<SQLName> columns = x.getColumns();
+
+        if (columns.size() > 0) {
+            print('(');
+        }
+        print0(ucase ? "VALUES " : "values ");
+        printAndAccept(x.getValues(), ", ");
+
+        if (columns.size() > 0) {
+            print(") ");
+        }
+
+        print0(ucase ? "AS " : "as ");
+        print0(x.getAlias());
+        print0(" (");
+        printAndAccept(columns, ", ");
+        print(')');
+
+        return false;
+    }
 }

src/main/java/com/alibaba/druid/sql/visitor/SQLASTVisitor.java

@@ -829,4 +829,7 @@ public interface SQLASTVisitor {
 
     boolean visit(SQLValuesExpr x);
     void endVisit(SQLValuesExpr x);
+
+    boolean visit(SQLValuesTableSource x);
+    void endVisit(SQLValuesTableSource x);
 }

src/main/java/com/alibaba/druid/sql/visitor/SQLASTVisitorAdapter.java

@@ -1964,6 +1964,15 @@ public class SQLASTVisitorAdapter implements SQLASTVisitor {
 
     }
 
+    @Override
+    public boolean visit(SQLValuesTableSource x) {
+        return true;
+    }
+
+    public void endVisit(SQLValuesTableSource x) {
+
+    }
+
     public final boolean isEnabled(VisitorFeature feature) {
         return VisitorFeature.isEnabled(this.features, feature);
     }

src/test/java/com/alibaba/druid/bvt/sql/clickhouse/ClickHouse_select_0.java

@@ -0,0 +1,44 @@
+package com.alibaba.druid.bvt.sql.clickhouse;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2SchemaStatVisitor;
+import com.alibaba.druid.util.JdbcConstants;
+import junit.framework.TestCase;
+
+import java.util.List;
+
+public class ClickHouse_select_0 extends TestCase {
+    public void test_0() throws Exception {
+        String sql = "SELECT date, transactionChannel, tranactionType FROM preComp_3All_20180322 limit 1,10";
+
+        List<SQLStatement> statementList = SQLUtils.parseStatements(sql, JdbcConstants.CLICKHOUSE);
+        SQLStatement stmt = statementList.get(0);
+
+        assertEquals(1, statementList.size());
+
+        DB2SchemaStatVisitor visitor = new DB2SchemaStatVisitor();
+        stmt.accept(visitor);
+
+//        System.out.println("Tables : " + visitor.getTables());
+//        System.out.println("fields : " + visitor.getColumns());
+//        System.out.println("coditions : " + visitor.getConditions());
+//        System.out.println("orderBy : " + visitor.getOrderByColumns());
+
+        assertEquals(1, visitor.getTables().size());
+        assertEquals(3, visitor.getColumns().size());
+        assertEquals(0, visitor.getConditions().size());
+
+        assertTrue(visitor.containsTable("preComp_3All_20180322"));
+
+        // assertTrue(visitor.getColumns().contains(new Column("mytable", "last_name")));
+        // assertTrue(visitor.getColumns().contains(new Column("mytable", "first_name")));
+        // assertTrue(visitor.getColumns().contains(new Column("mytable", "full_name")));
+
+        String output = SQLUtils.toSQLString(stmt, JdbcConstants.CLICKHOUSE);
+        assertEquals("SELECT date, transactionChannel, tranactionType\n" +
+                        "FROM preComp_3All_20180322\n" +
+                        "LIMIT 1, 10", //
+                output);
+    }
+}

src/test/java/com/alibaba/druid/bvt/sql/cobar/DMLSelectParserTest.java

@@ -39,7 +39,8 @@ public class DMLSelectParserTest extends TestCase {
                 "UNION ALL\n" +
                 "(SELECT id\n" +
                 "FROM t3)\n" +
-                "ORDER BY d DESC", output);
+                "ORDER BY d DESC\n" +
+                "LIMIT ?, 1", output);
     }
 
     public void test_union_1() throws Exception {

src/test/java/com/alibaba/druid/bvt/sql/postgresql/PGDeleteTest10.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 1999-2017 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.postgresql;
+
+import com.alibaba.druid.sql.PGTest;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.postgresql.parser.PGSQLStatementParser;
+import com.alibaba.druid.sql.dialect.postgresql.visitor.PGSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+
+import java.util.List;
+
+public class PGDeleteTest10 extends PGTest {
+
+    public void test_0() throws Exception {
+        String sql = "delete from account a using (values (1), (7)) as tmp(id) WHERE a.id = tmp.id";
+
+        PGSQLStatementParser parser = new PGSQLStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+
+        assertEquals("DELETE FROM account AS a\n" +
+                "USING (VALUES (1), (7)) AS tmp (id)\n" +
+                "WHERE a.id = tmp.id", stmt.toString());
+
+        assertEquals(1, statementList.size());
+
+        PGSchemaStatVisitor visitor = new PGSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+//        System.out.println("coditions : " + visitor.getConditions());
+
+        assertTrue(visitor.getTables().containsKey(new TableStat.Name("account")));
+
+        assertEquals(2, visitor.getColumns().size() );
+        
+        assertTrue(visitor.containsColumn("account", "id"));
+    }
+
+    
+}

src/test/java/com/alibaba/druid/bvt/sql/schemaStat/SchemaStatTest14.java

@@ -17,13 +17,11 @@ public class SchemaStatTest14 extends TestCase {
     public void test_schemaStat() throws Exception {
         String sql = "delete r from t_res r where id=1 ";
 
-        String dbType = JdbcConstants.MYSQL;
-        SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, dbType);
-        SQLStatement stmt = parser.parseStatementList().get(0);
+        SQLStatement stmt = SQLUtils.parseStatements(sql, JdbcConstants.MYSQL).get(0);
 
         System.out.println(stmt);
 
-        SchemaStatVisitor statVisitor = SQLUtils.createSchemaStatVisitor(dbType);
+        SchemaStatVisitor statVisitor = SQLUtils.createSchemaStatVisitor(JdbcConstants.MYSQL);
         stmt.accept(statVisitor);
 
         Set<TableStat.Relationship> relationships = statVisitor.getRelationships();