fix bugs

migrations/mysql/02129_payment_sort.sql

@@ -1,4 +1,3 @@
--- migrate:up
 SET @column_exists = (
     SELECT COUNT(*)
     FROM INFORMATION_SCHEMA.COLUMNS
@@ -21,22 +20,3 @@ UPDATE `payment`
 SET `sort` = `id`
 WHERE `sort` = 0;
 
--- migrate:down
-SET @column_exists = (
-    SELECT COUNT(*)
-    FROM INFORMATION_SCHEMA.COLUMNS
-    WHERE TABLE_SCHEMA = DATABASE()
-      AND TABLE_NAME = 'payment'
-      AND COLUMN_NAME = 'sort'
-);
-
-SET @sql = IF(
-    @column_exists > 0,
-    'ALTER TABLE `payment` DROP COLUMN `sort`',
-    'SELECT 1'
-);
-
-PREPARE stmt FROM @sql;
-EXECUTE stmt;
-DEALLOCATE PREPARE stmt;
-