fixed mysql sql migration script error

scripts/migration/mysql/0011_home_timeline.down.sql

@@ -2,18 +2,14 @@ DROP TABLE IF EXISTS `p_post_metric`;
 
 -- 原来的可见性: 0公开 1私密 2好友可见 3关注可见
 -- 现在的可见性: 0私密 10充电可见 20订阅可见 30保留 40保留 50好友可见 60关注可见 70保留 80保留 90公开
-UPDATE p_post a 
-SET visibility = (
-	SELECT
-	CASE visibility 
+UPDATE p_post a, p_post b 
+SET a.visibility = (
+	CASE b.visibility 
 		WHEN 90 THEN 0 
 		WHEN 0 THEN 1 
 		WHEN 50 THEN 2 
 		WHEN 60 THEN 3 
 		ELSE 0
 	END 
-	FROM
-		p_post b 
-	WHERE
-		a.ID = b.ID 
-);
+)
+WHERE a.ID = b.ID;

scripts/migration/mysql/0011_home_timeline.up.sql

@@ -22,18 +22,14 @@ WHERE is_del=0;
 
 -- 原来的可见性: 0公开 1私密 2好友可见 3关注可见
 -- 现在的可见性: 0私密 10充电可见 20订阅可见 30保留 40保留 50好友可见 60关注可见 70保留 80保留 90公开
-UPDATE p_post a 
-SET visibility = (
-	SELECT
-	CASE visibility 
+UPDATE p_post a, p_post b 
+SET a.visibility = (
+	CASE b.visibility 
 		WHEN 0 THEN 90 
 		WHEN 1 THEN 0 
 		WHEN 2 THEN 50 
 		WHEN 3 THEN 60 
 		ELSE 0
 	END 
-	FROM
-		p_post b 
-	WHERE
-		a.ID = b.ID 
-);
+)
+WHERE a.ID = b.ID;