improved sql parser.

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

@@ -17,4 +17,8 @@ package com.alibaba.druid.sql.ast;
 
 public interface SQLStatement extends SQLObject {
     String getDbType();
+
+    boolean isAfterSemi();
+
+    void setAfterSemi(boolean afterSemi);
 }

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

@@ -22,6 +22,8 @@ public abstract class SQLStatementImpl extends SQLObjectImpl implements SQLState
 
     private String dbType;
 
+    private boolean afterSemi;
+
     public SQLStatementImpl(){
 
     }
@@ -46,4 +48,12 @@ public abstract class SQLStatementImpl extends SQLObjectImpl implements SQLState
     protected void accept0(SQLASTVisitor visitor) {
         throw new UnsupportedOperationException(this.getClass().getName());
     }
+
+    public boolean isAfterSemi() {
+        return afterSemi;
+    }
+
+    public void setAfterSemi(boolean afterSemi) {
+        this.afterSemi = afterSemi;
+    }
 }

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

@@ -26,6 +26,8 @@ import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 public class SQLBlockStatement extends SQLStatementImpl {
     private String             labelName;
 
+    private String endLabel;
+
     private List<SQLParameter> parameters    = new ArrayList<SQLParameter>();
 
     private List<SQLStatement> statementList = new ArrayList<SQLStatement>();
@@ -73,4 +75,12 @@ public class SQLBlockStatement extends SQLStatementImpl {
     public void setException(SQLStatement exception) {
         this.exception = exception;
     }
+
+    public String getEndLabel() {
+        return endLabel;
+    }
+
+    public void setEndLabel(String endLabel) {
+        this.endLabel = endLabel;
+    }
 }

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

@@ -20,7 +20,7 @@ import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.SQLStatementImpl;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class SQLCommentStatement extends SQLStatementImpl implements SQLStatement {
+public class SQLCommentStatement extends SQLStatementImpl {
 
     public static enum Type {
         TABLE, COLUMN

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

@@ -1,3 +1,18 @@
+/*
+ * 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.ast.statement;
 
 import com.alibaba.druid.sql.ast.*;

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

@@ -72,6 +72,9 @@ public class SQLIfStatement extends SQLStatementImpl {
     }
 
     public void setElseItem(Else elseItem) {
+        if (elseItem != null) {
+            elseItem.setParent(this);
+        }
         this.elseItem = elseItem;
     }
 

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

@@ -28,6 +28,8 @@ public class SQLInsertStatement extends SQLInsertInto implements SQLStatement {
 
     protected boolean upsert = false; // for phoenix
 
+    private boolean afterSemi;
+
     public SQLInsertStatement(){
 
     }
@@ -105,4 +107,14 @@ public class SQLInsertStatement extends SQLInsertInto implements SQLStatement {
     public void setDbType(String dbType) {
         this.dbType = dbType;
     }
+
+    @Override
+    public boolean isAfterSemi() {
+        return afterSemi;
+    }
+
+    @Override
+    public void setAfterSemi(boolean afterSemi) {
+        this.afterSemi = afterSemi;
+    }
 }

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

@@ -0,0 +1,52 @@
+/*
+ * 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.ast.statement;
+
+import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLStatementImpl;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLReturnStatement extends SQLStatementImpl {
+
+    private SQLExpr expr;
+
+    public SQLReturnStatement() {
+
+    }
+
+    public SQLReturnStatement(String dbType) {
+        super (dbType);
+    }
+
+    public SQLExpr getExpr() {
+        return expr;
+    }
+
+    public void setExpr(SQLExpr expr) {
+        if (expr != null) {
+            expr.setParent(this);
+        }
+        this.expr = expr;
+    }
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, expr);
+        }
+        visitor.endVisit(this);
+    }
+}

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

@@ -20,7 +20,7 @@ import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.SQLStatementImpl;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class SQLUseStatement extends SQLStatementImpl implements SQLStatement {
+public class SQLUseStatement extends SQLStatementImpl {
 
     private SQLName database;