improved mysql parser

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

@@ -757,6 +757,13 @@ public class MySqlExprParser extends SQLExprParser {
             SQLName indexName = name();
             unique.setIndexName(indexName);
         }
+        
+        //5.5语法 USING BTREE 放在index 名字后
+        if (identifierEquals("USING")) {
+            lexer.nextToken();
+            unique.setIndexType(lexer.stringVal());
+            lexer.nextToken();
+        }
 
         accept(Token.LPAREN);
         for (;;) {

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlCreateTableTest64.java

@@ -0,0 +1,46 @@
+/*
+ * 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 org.junit.Assert;
+import org.junit.Test;
+
+import com.alibaba.druid.sql.MysqlTest;
+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.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+
+public class MySqlCreateTableTest64 extends MysqlTest {
+
+    @Test
+    public void test_one() throws Exception {
+        String sql = "create table t (c char(10) ,unique key a using hash (c(1))) charset = utf8mb4 engine=heap;";
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        SQLStatement stmt = parser.parseCreateTable();
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        String output = SQLUtils.toMySqlString(stmt);
+        Assert.assertEquals("CREATE TABLE t ("
+                + "\n\tc char(10), "
+                + "\n\tUNIQUE a USING hash (c(1))"
+                + "\n) CHARSET = utf8mb4 ENGINE = heap", output);
+
+    }
+}