improved odps sql parser, support more 'change column' syntax.

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

@@ -17,10 +17,12 @@
 package com.alibaba.druid.sql.ast.statement;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLObjectImpl;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class SQLAlterTableAlterColumn extends SQLObjectImpl implements SQLAlterTableItem {
+    private SQLName             originColumn;
 
     private SQLColumnDefinition column;
 
@@ -81,4 +83,14 @@ public class SQLAlterTableAlterColumn extends SQLObjectImpl implements SQLAlterT
         this.dropDefault = dropDefault;
     }
 
+    public SQLName getOriginColumn() {
+        return originColumn;
+    }
+
+    public void setOriginColumn(SQLName originColumn) {
+        if (originColumn != null) {
+            originColumn.setParent(this);
+        }
+        this.originColumn = originColumn;
+    }
 }

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

@@ -42,6 +42,9 @@ public class SQLAlterTableRenameColumn extends SQLObjectImpl implements SQLAlter
     }
 
     public void setColumn(SQLName column) {
+        if (column != null) {
+            column.setParent(this);
+        }
         this.column = column;
     }
 
@@ -50,6 +53,9 @@ public class SQLAlterTableRenameColumn extends SQLObjectImpl implements SQLAlter
     }
 
     public void setTo(SQLName to) {
+        if (to != null) {
+            to.setParent(this);
+        }
         this.to = to;
     }
 

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

@@ -888,4 +888,13 @@ public class OdpsOutputVisitor extends SQLASTOutputVisitor implements OdpsASTVis
 
         return false;
     }
+
+    @Override
+    public boolean visit(SQLAlterTableRenameColumn x) {
+        print0(ucase ? "CHANGE COLUMN " : "change column ");
+        x.getColumn().accept(this);
+        print0(ucase ? " RENAME TO " : " rename to ");
+        x.getTo().accept(this);
+        return false;
+    }
 }

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

@@ -885,18 +885,38 @@ public class SQLStatementParser extends SQLParser {
                     lexer.nextToken();
                     accept(Token.COLUMN);
                     SQLName columnName = this.exprParser.name();
-                    accept(Token.COMMENT);
-                    SQLExpr comment = this.exprParser.primary();
 
-                    SQLColumnDefinition columnDefinition = new SQLColumnDefinition();
-                    columnDefinition.setName(columnName);
-                    columnDefinition.setComment(comment);
+                    if (identifierEquals("RENAME")) {
+                        lexer.nextToken();
+                        accept(Token.TO);
+                        SQLName toName = this.exprParser.name();
+                        SQLAlterTableRenameColumn renameColumn = new SQLAlterTableRenameColumn();
 
-                    SQLAlterTableAlterColumn changeColumn = new SQLAlterTableAlterColumn();
+                        renameColumn.setColumn(columnName);
+                        renameColumn.setTo(toName);
 
-                    changeColumn.setColumn(columnDefinition);
+                        stmt.addItem(renameColumn);
+                    } else if (lexer.token() == Token.COMMENT) {
+                        lexer.nextToken();
+                        SQLExpr comment = this.exprParser.primary();
 
-                    stmt.addItem(changeColumn);
+                        SQLColumnDefinition columnDefinition = new SQLColumnDefinition();
+                        columnDefinition.setName(columnName);
+                        columnDefinition.setComment(comment);
+
+                        SQLAlterTableAlterColumn changeColumn = new SQLAlterTableAlterColumn();
+
+                        changeColumn.setColumn(columnDefinition);
+
+                        stmt.addItem(changeColumn);
+                    } else {
+                        SQLColumnDefinition column = this.exprParser.parseColumn();
+
+                        SQLAlterTableAlterColumn alterColumn = new SQLAlterTableAlterColumn();
+                        alterColumn.setColumn(column);
+                        alterColumn.setOriginColumn(columnName);
+                        stmt.addItem(alterColumn);
+                    }
                 } else if (lexer.token() == Token.WITH) {
                     lexer.nextToken();
                     acceptIdentifier("NOCHECK");