bug fixed for mysql parser, support 'add constraint unique' syntax. fixed issue #1339

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

@@ -84,6 +84,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLShowTablesStatement;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
+import com.alibaba.druid.sql.ast.statement.SQLUnique;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.MysqlForeignKey;
@@ -2371,6 +2372,10 @@ public class MySqlStatementParser extends SQLStatementParser {
 
                         SQLAlterTableAddConstraint item = new SQLAlterTableAddConstraint(fk);
 
+                        stmt.addItem(item);
+                    } else if (lexer.token() == Token.UNIQUE) {
+                        SQLUnique unique = this.exprParser.parseUnique();
+                        SQLAlterTableAddConstraint item = new SQLAlterTableAddConstraint(unique);
                         stmt.addItem(item);
                     } else {
                         throw new ParserException("TODO " + lexer.token() + " " + lexer.stringVal());

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlAlterTableAddUniqueTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 1999-2101 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.mysql;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.parser.Token;
+
+public class MySqlAlterTableAddUniqueTest extends TestCase {
+
+    public void test_alter_first() throws Exception {
+        String sql = "ALTER TABLE icp.wx_msg ADD CONSTRAINT idx_msgId_msgType_event_eventKey UNIQUE (msgId, msgType, event, eventKey)";
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        SQLStatement stmt = parser.parseStatementList().get(0);
+        parser.match(Token.EOF);
+        
+        Assert.assertEquals("ALTER TABLE icp.wx_msg"
+                + "\n\tADD UNIQUE (msgId, msgType, event, eventKey)", SQLUtils.toMySqlString(stmt));
+        
+        Assert.assertEquals("alter table icp.wx_msg"
+                + "\n\tadd unique (msgId, msgType, event, eventKey)", SQLUtils.toMySqlString(stmt, SQLUtils.DEFAULT_LCASE_FORMAT_OPTION));
+    }
+
+}