improved sql parser.

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

@@ -444,7 +444,9 @@ public class PagerUtils {
     }
 
     private static SQLSelectQueryBlock createQueryBlock(String dbType) {
-        if (JdbcConstants.MYSQL.equals(dbType)) {
+        if (JdbcConstants.MYSQL.equals(dbType)
+                || JdbcConstants.MARIADB.equals(dbType)
+                || JdbcConstants.ALIYUN_ADS.equals(dbType)) {
             return new MySqlSelectQueryBlock();
         }
 

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

@@ -48,6 +48,14 @@ public class SQLMethodInvokeExpr extends SQLExprImpl implements SQLReplaceable,
         setOwner(owner);
     }
 
+    public SQLMethodInvokeExpr(String methodName, SQLExpr owner, SQLExpr... params){
+        this.methodName = methodName;
+        setOwner(owner);
+        for (SQLExpr param : params) {
+            this.addParameter(param);
+        }
+    }
+
     public String getMethodName() {
         return this.methodName;
     }

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

@@ -15,6 +15,7 @@
  */
 package com.alibaba.druid.sql.ast.statement;
 
+import com.alibaba.druid.sql.SQLUtils;
 import com.alibaba.druid.sql.ast.SQLCommentHint;
 import com.alibaba.druid.sql.ast.SQLDataTypeImpl;
 import com.alibaba.druid.sql.ast.SQLExpr;
@@ -99,4 +100,9 @@ public class SQLCharacterDataType extends SQLDataTypeImpl {
 
         visitor.endVisit(this);
     }
+
+    @Override
+    public String toString() {
+        return SQLUtils.toSQLString(this);
+    }
 }

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

@@ -103,6 +103,9 @@ public class SQLColumnDefinition extends SQLObjectImpl implements SQLTableElemen
     }
 
     public void setDataType(SQLDataType dataType) {
+        if (dataType != null) {
+            dataType.setParent(this);
+        }
         this.dataType = dataType;
     }
 

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

@@ -227,4 +227,14 @@ public class SQLCreateTableStatement extends SQLStatementImpl implements SQLDDLS
             }
         }
     }
+
+    public SQLPrimaryKey findPrimaryKey() {
+        for (SQLTableElement element : this.tableElementList) {
+            if (element instanceof SQLPrimaryKey) {
+                return (SQLPrimaryKey) element;
+            }
+        }
+
+        return null;
+    }
 }

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

@@ -22,6 +22,7 @@ import com.alibaba.druid.sql.SQLUtils;
 import com.alibaba.druid.sql.ast.*;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery, SQLReplaceable {
@@ -89,6 +90,18 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         }
         this.where = where;
     }
+
+    public void addWhere(SQLExpr condition) {
+        if (condition == null) {
+            return;
+        }
+
+        if (where == null) {
+            where = condition;
+        } else {
+            where = SQLBinaryOpExpr.and(where, condition);
+        }
+    }
     
     public SQLOrderBy getOrderBy() {
         return orderBy;
@@ -448,4 +461,14 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
 
         this.setWhere(SQLBinaryOpExpr.and(where, expr));
     }
+
+    public void limit(int rowCount, int offset) {
+        SQLLimit limit = new SQLLimit();
+        limit.setRowCount(new SQLIntegerExpr(rowCount));
+        if (offset > 0) {
+            limit.setOffset(new SQLIntegerExpr(offset));
+        }
+
+        setLimit(limit);
+    }
 }

src/main/java/com/alibaba/druid/sql/builder/FunctionBuilder.java

@@ -0,0 +1,78 @@
+/*
+ * 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.sql.builder;
+
+import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
+import com.alibaba.druid.util.JdbcConstants;
+
+/**
+ * Created by wenshao on 09/07/2017.
+ */
+public class FunctionBuilder {
+    private final String dbType;
+
+    public FunctionBuilder(String dbType) {
+        this.dbType = dbType;
+    }
+
+    // for character function
+    public SQLMethodInvokeExpr length(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("length", null, expr);
+    }
+
+    public SQLMethodInvokeExpr lower(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("lower", null, expr);
+    }
+
+    public SQLMethodInvokeExpr upper(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("upper", null, expr);
+    }
+
+    public SQLMethodInvokeExpr substr(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("substr", null, expr);
+    }
+
+    public SQLMethodInvokeExpr ltrim(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("ltrim", null, expr);
+    }
+
+    public SQLMethodInvokeExpr rtrim(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("rtrim", null, expr);
+    }
+
+    public SQLMethodInvokeExpr trim(SQLExpr expr) {
+        return new SQLMethodInvokeExpr("trim", null, expr);
+    }
+
+    public SQLMethodInvokeExpr ifnull(SQLExpr expr1, SQLExpr expr2) {
+        if (JdbcConstants.ALIYUN_ADS.equals(dbType)
+                || JdbcConstants.PRESTO.equals(dbType)
+                || JdbcConstants.ODPS.equals(dbType)) {
+            return new SQLMethodInvokeExpr("coalesce", null, expr1, expr2);
+        }
+
+        if (JdbcConstants.ORACLE.equals(dbType)) {
+            return new SQLMethodInvokeExpr("nvl", null, expr1, expr2);
+        }
+
+        if (JdbcConstants.SQL_SERVER.equals(dbType)) {
+            return new SQLMethodInvokeExpr("isnull", null, expr1, expr2);
+        }
+
+        return new SQLMethodInvokeExpr("ifnull", null, expr1, expr2);
+    }
+}

src/main/java/com/alibaba/druid/sql/builder/impl/SQLSelectBuilderImpl.java

@@ -194,11 +194,7 @@ public class SQLSelectBuilderImpl implements SQLSelectBuilder {
     @Override
     public SQLSelectBuilderImpl whereAnd(String expr) {
         SQLSelectQueryBlock queryBlock = getQueryBlock();
-
-        SQLExpr exprObj = SQLUtils.toSQLExpr(expr, dbType);
-        SQLExpr newCondition = SQLUtils.buildCondition(SQLBinaryOperator.BooleanAnd, exprObj, false,
-                                                       queryBlock.getWhere());
-        queryBlock.setWhere(newCondition);
+        queryBlock.addWhere(SQLUtils.toSQLExpr(expr, dbType));
 
         return this;
     }
@@ -222,86 +218,9 @@ public class SQLSelectBuilderImpl implements SQLSelectBuilder {
 
     @Override
     public SQLSelectBuilderImpl limit(int rowCount, int offset) {
-        SQLSelectQueryBlock queryBlock = getQueryBlock();
-
-        if (queryBlock instanceof MySqlSelectQueryBlock) {
-            MySqlSelectQueryBlock mySqlQueryBlock = (MySqlSelectQueryBlock) queryBlock;
-
-            SQLLimit limit = new SQLLimit();
-            limit.setRowCount(new SQLIntegerExpr(rowCount));
-            if (offset > 0) {
-                limit.setOffset(new SQLIntegerExpr(offset));
-            }
-
-            mySqlQueryBlock.setLimit(limit);
-
-            return this;
-        }
-
-        if (queryBlock instanceof SQLServerSelectQueryBlock) {
-            SQLServerSelectQueryBlock sqlserverQueryBlock = (SQLServerSelectQueryBlock) queryBlock;
-            if (offset <= 0) {
-                SQLServerTop top = new SQLServerTop();
-                top.setExpr(new SQLIntegerExpr(rowCount));
-                sqlserverQueryBlock.setTop(top);
-            } else {
-                throw new UnsupportedOperationException("not support offset");
-            }
-
-            return this;
-        }
-
-        if (queryBlock instanceof PGSelectQueryBlock) {
-            PGSelectQueryBlock pgQueryBlock = (PGSelectQueryBlock) queryBlock;
-            SQLLimit limit = new SQLLimit();
-            if (offset > 0) {
-                limit.setOffset(new SQLIntegerExpr(offset));
-            }
-            limit.setRowCount(new SQLIntegerExpr(rowCount));
-            pgQueryBlock.setLimit(limit);
-
-            return this;
-        }
-
-        if (queryBlock instanceof DB2SelectQueryBlock) {
-            DB2SelectQueryBlock db2QueryBlock = (DB2SelectQueryBlock) queryBlock;
-            if (offset <= 0) {
-                SQLExpr rowCountExpr = new SQLIntegerExpr(rowCount);
-                db2QueryBlock.setFirst(rowCountExpr);
-            } else {
-                throw new UnsupportedOperationException("not support offset");
-            }
-
-            return this;
-        }
-
-        if (queryBlock instanceof OracleSelectQueryBlock) {
-            OracleSelectQueryBlock oracleQueryBlock = (OracleSelectQueryBlock) queryBlock;
-            if (offset <= 0) {
-                SQLExpr rowCountExpr = new SQLIntegerExpr(rowCount);
-                SQLExpr newCondition = SQLUtils.buildCondition(SQLBinaryOperator.BooleanAnd, rowCountExpr, false,
-                                                               oracleQueryBlock.getWhere());
-                queryBlock.setWhere(newCondition);
-            } else {
-                throw new UnsupportedOperationException("not support offset");
-            }
-
-            return this;
-        }
-        
-        if (queryBlock instanceof OdpsSelectQueryBlock) {
-            OdpsSelectQueryBlock odpsQueryBlock = (OdpsSelectQueryBlock) queryBlock;
-
-            if (offset > 0) {
-                throw new UnsupportedOperationException("not support offset");
-            }
-
-            odpsQueryBlock.setLimit(new SQLLimit(new SQLIntegerExpr(rowCount)));
-
-            return this;
-        }
-
-        throw new UnsupportedOperationException();
+        getQueryBlock()
+                .limit(rowCount, offset);
+        return this;
     }
 
     protected SQLSelectQueryBlock getQueryBlock() {

src/main/java/com/alibaba/druid/sql/dialect/db2/ast/stmt/DB2SelectQueryBlock.java

@@ -16,6 +16,7 @@
 package com.alibaba.druid.sql.dialect.db2.ast.stmt;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.db2.ast.DB2Object;
 import com.alibaba.druid.sql.dialect.db2.visitor.DB2ASTVisitor;
@@ -80,4 +81,12 @@ public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Objec
     public static enum Isolation {
         RR, RS, CS, UR
     }
+
+    public void limit(int rowCount, int offset) {
+        if (offset <= 0) {
+            setFirst(new SQLIntegerExpr(rowCount));
+        } else {
+            throw new UnsupportedOperationException("not support offset");
+        }
+    }
 }

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

@@ -328,9 +328,10 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             dataType.accept(this);
         }
 
-        if (x.getCharsetExpr() != null) {
+        final SQLExpr charsetExpr = x.getCharsetExpr();
+        if (charsetExpr != null) {
             print0(ucase ? " CHARSET " : " charset ");
-            x.getCharsetExpr().accept(this);
+            charsetExpr.accept(this);
         }
 
         for (SQLColumnConstraint item : x.getConstraints()) {
@@ -338,20 +339,23 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             item.accept(this);
         }
 
-        if (x.getDefaultExpr() != null) {
+        final SQLExpr defaultExpr = x.getDefaultExpr();
+        if (defaultExpr != null) {
             print0(ucase ? " DEFAULT " : " default ");
-            x.getDefaultExpr().accept(this);
+            defaultExpr.accept(this);
         }
 
-        if (x.getStorage() != null) {
+        final SQLExpr storage = x.getStorage();
+        if (storage != null) {
             print0(ucase ? " STORAGE " : " storage ");
-            x.getStorage().accept(this);
+            storage.accept(this);
         }
 
-        if (x.getOnUpdate() != null) {
+        SQLExpr onUpdate = x.getOnUpdate();
+        if (onUpdate != null) {
             print0(ucase ? " ON UPDATE " : " on update ");
 
-            x.getOnUpdate().accept(this);
+            onUpdate.accept(this);
         }
 
         if (x.isAutoIncrement()) {

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

@@ -21,7 +21,9 @@ import java.util.List;
 import com.alibaba.druid.sql.SQLUtils;
 import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLHint;
+import com.alibaba.druid.sql.ast.SQLLimit;
 import com.alibaba.druid.sql.ast.SQLOrderBy;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectOrderByItem;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.odps.visitor.OdpsASTVisitor;
@@ -122,4 +124,12 @@ public class OdpsSelectQueryBlock extends SQLSelectQueryBlock {
     public String toString() {
         return SQLUtils.toOdpsString(this);
     }
+
+    public void limit(int rowCount, int offset) {
+        if (offset > 0) {
+            throw new UnsupportedOperationException("not support offset");
+        }
+
+        setLimit(new SQLLimit(new SQLIntegerExpr(rowCount)));
+    }
 }

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

@@ -21,6 +21,9 @@ import java.util.List;
 import com.alibaba.druid.sql.SQLUtils;
 import com.alibaba.druid.sql.ast.SQLCommentHint;
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLLimit;
+import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.oracle.ast.clause.ModelClause;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
@@ -147,4 +150,15 @@ public class OracleSelectQueryBlock extends SQLSelectQueryBlock {
     public String toString() {
         return SQLUtils.toOracleString(this);
     }
+
+    public void limit(int rowCount, int offset) {
+        if (offset <= 0) {
+            SQLExpr rowCountExpr = new SQLIntegerExpr(rowCount);
+            SQLExpr newCondition = SQLUtils.buildCondition(SQLBinaryOperator.BooleanAnd, rowCountExpr, false,
+                    where);
+            setWhere(newCondition);
+        } else {
+            throw new UnsupportedOperationException("not support offset");
+        }
+    }
 }

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

@@ -15,6 +15,8 @@
  */
 package com.alibaba.druid.sql.dialect.sqlserver.ast;
 
+import com.alibaba.druid.sql.ast.SQLLimit;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -34,6 +36,10 @@ public class SQLServerSelectQueryBlock extends SQLSelectQueryBlock {
         this.top = top;
     }
 
+    public void setTop(int rowCount) {
+        setTop(new SQLServerTop(new SQLIntegerExpr(rowCount)));
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         accept0((SQLServerASTVisitor) visitor);
@@ -49,4 +55,12 @@ public class SQLServerSelectQueryBlock extends SQLSelectQueryBlock {
         }
         visitor.endVisit(this);
     }
+
+    public void limit(int rowCount, int offset) {
+        if (offset <= 0) {
+            setTop(rowCount);
+        } else {
+            throw new UnsupportedOperationException("not support offset");
+        }
+    }
 }

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

@@ -343,6 +343,16 @@ public class Lexer {
             }
 
             if (isFirstIdentifierChar(ch)) {
+                if (ch == '（') {
+                    scanChar();
+                    token = LPAREN;
+                    return;
+                } else if (ch == '）') {
+                    scanChar();
+                    token = RPAREN;
+                    return;
+                }
+
                 if (ch == 'N') {
                     if (charAt(pos + 1) == '\'') {
                         ++pos;

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

@@ -110,7 +110,11 @@ public class SchemaRepository {
             String name = x.computeName();
             SchemaObject object = new SchemaObjectImpl(name, SchemaObjectType.Table, x);
 
-            objects.put(name.toLowerCase(), object);
+            String name_lower = name.toLowerCase();
+            if (objects.containsKey(name_lower)) {
+                return false;
+            }
+            objects.put(name_lower, object);
 
             return false;
         }

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

@@ -99,4 +99,9 @@ public interface JdbcConstants {
 
     public static final String SQLITE              = "sqlite";
     public static final String SQLITE_DRIVER       = "org.sqlite.JDBC";
+
+    public static final String ALIYUN_ADS          = "aliyun_ads";
+    public static final String ALIYUN_DRDS         = "aliyun_drds";
+
+    public static final String PRESTO              = "presto";
 }