fix #205 create index rewrite error

  https://github.com/XiaoMi/soar/issues/205

ast/rewrite.go

@@ -1688,7 +1688,6 @@ func MergeAlterTables(sqls ...string) map[string]string {
 	// CREATE [UNIQUE|FULLTEXT|SPATIAL|PRIMARY] [KEY|INDEX] idx_name ON tbl_name
 	createIndexExp := regexp.MustCompile(`(?i)create((unique)|(fulltext)|(spatial)|(primary)|(\s*)\s*)((index)|(key))\s*`)
 	indexNameExp := regexp.MustCompile(`(?i)(` + backTicks + `|([^\s]*))\s*`)
-	indexColsExp := regexp.MustCompile(`(?i)(` + backTicks + `|([^\s]*))\s*on\s*(` + backTicks + `|([^\s]*))\s*`)
 
 	for _, sql := range sqls {
 		sql = strings.Trim(sql, common.Config.Delimiter)
@@ -1719,7 +1718,8 @@ func MergeAlterTables(sqls ...string) map[string]string {
 				} else if createIndexExp.MatchString(sql) {
 					buf := createIndexExp.ReplaceAllString(sql, "")
 					idxName := strings.TrimSpace(indexNameExp.FindString(buf))
-					buf = indexColsExp.ReplaceAllString(buf, "")
+					buf = string([]byte(buf)[strings.Index(buf, "("):])
+					common.Log.Error(buf)
 					common.Log.Debug("alter createIndexExp: ALTER %v ADD INDEX %v %v", tableName, "ADD INDEX", idxName, buf)
 					alterSQL = fmt.Sprint("ADD INDEX", " "+idxName+" ", buf)
 				}

ast/rewrite_test.go

@@ -631,6 +631,7 @@ func TestMergeAlterTables(t *testing.T) {
 		// ADD|DROP INDEX
 		// TODO: PRIMARY KEY, [UNIQUE|FULLTEXT|SPATIAL] INDEX
 		"CREATE INDEX part_of_name ON customer (name(10));",
+		"create index idx_test_cca on test_bb(test_cc);", // https://github.com/XiaoMi/soar/issues/205
 		"alter table `sakila`.`t1` add index `idx_col`(`col`)",
 		"alter table `sakila`.`t1` add UNIQUE index `idx_col`(`col`)",
 		"alter table `sakila`.`t1` add index `idx_ID`(`ID`)",

ast/testdata/TestMergeAlterTables.golden

@@ -8,3 +8,5 @@
 
 `t3` : ALTER TABLE `t3` add index `idx_a`(a), drop index`idx_b`(b) ;
 
+`test_bb` : ALTER TABLE `test_bb` ADD INDEX idx_test_cca (test_cc) ;
+