improved mysql parser, support alter table union options

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

@@ -16,9 +16,12 @@
 package com.alibaba.druid.sql.ast.statement;
 
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 
 import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.ast.SQLObject;
 import com.alibaba.druid.sql.ast.SQLStatementImpl;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
@@ -35,6 +38,7 @@ public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLSt
 
     private boolean                 removePatiting          = false;
     private boolean                 upgradePatiting         = false;
+    private Map<String, SQLObject>  tableOptions            = new LinkedHashMap<String, SQLObject>();
 
     public SQLAlterTableStatement(){
 
@@ -114,6 +118,10 @@ public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLSt
         this.setTableSource(new SQLExprTableSource(name));
     }
 
+    public Map<String, SQLObject> getTableOptions() {
+        return tableOptions;
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {

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

@@ -33,7 +33,6 @@ import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
-import com.alibaba.druid.sql.ast.expr.SQLListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNCharExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
@@ -2751,6 +2750,16 @@ public class MySqlStatementParser extends SQLStatementParser {
                 }
                 stmt.addItem(new MySqlAlterTableOption("COMMENT", '\'' + lexer.stringVal() + '\''));
                 lexer.nextToken();
+            } else if (lexer.token() == Token.UNION) {
+                lexer.nextToken();
+                if (lexer.token() == Token.EQ) {
+                    lexer.nextToken();
+                }
+
+                accept(Token.LPAREN);
+                SQLTableSource tableSrc = this.createSQLSelectParser().parseTableSource();
+                stmt.getTableOptions().put("UNION", tableSrc);
+                accept(Token.RPAREN);
             } else {
                 break;
             }

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

@@ -2487,7 +2487,37 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             print0(ucase ? "UPGRADE PARTITIONING" : "upgrade partitioning");
         }
         
+        if (x.getTableOptions().size() > 0) {
+            println();
+        }
+        
         decrementIndent();
+        
+        int i = 0;
+        for (Map.Entry<String, SQLObject> option : x.getTableOptions().entrySet()) {
+            String key = option.getKey();
+            if (i != 0) {
+                print(' ');
+            }
+            print0(ucase ? key : key.toLowerCase());
+
+            if ("TABLESPACE".equals(key)) {
+                print(' ');
+                option.getValue().accept(this);
+                continue;
+            } else if ("UNION".equals(key)) {
+                print0(" = (");
+                option.getValue().accept(this);
+                print(')');
+                continue;
+            }
+
+            print0(" = ");
+
+            option.getValue().accept(this);
+            i++;
+        }
+        
         return false;
     }