MySQL IF 表达式返回错误

Question

SELECT last_played INTO @lp FROM sr WHERE creator_id = 1 AND playing = 1 LIMIT 1;
SELECT stream_id INTO @sid FROM account_stream WHERE owner = 1 AND enabled = 1 LIMIT 1;
UPDATE sr SET last_played = 1412259166 WHERE creator_id = 1 AND playing = 1 LIMIT 1;
IF @lp != NULL THEN UPDATE streams SET duration = (duration + (1412259166 - @lp)) WHERE id = @sid LIMIT 1; END IF;

我想做的事情:当@lp返回某些内容时(换句话说，当第一个查询中的playing为1时)，然后执行最后一个更新流查询。

我在 phpmyadmin 中收到此错误:

1064 - 您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，了解在第 1 行的 'IF @lp != 0 THEN UPDATE Streams SETuration = (duration + (1412259166 - @lp)) W' 附近使用的正确语法

我以前从未使用过 mysql if 条件，所以，有人可以帮助我吗？

Answer 1

 UPDATE streams SET duration = (duration + (1412259166 - @lp)) 
 WHERE @lp IS NOT NULL AND id = @sid