帮助转换SQL嵌套子查询以加入MySQL 4.0兼容性的查询

Question

我有一个嵌套的SQL查询：

SELECT DISTINCT(topic_id)
FROM bb_posts 
WHERE topic_id NOT IN ( 
  SELECT topic_id FROM bb_posts 
  WHERE poster_id = $user_id AND post_status = 0 ) 
ORDER BY post_time DESC

我的Web服务器运行MySQL 4.0，不允许嵌套查询。一些SQL Guru可以使用Join Lingo建议相同的查询吗？我尝试并尝试了...但是我无法弄清楚。感到愚蠢。

Answer 1

假设主题_ID不是无效的，您可以做：

SELECT DISTINCT(T1.topic_id)
FROM bb_posts As T1
    Left Join bb_posts As T2
        On T2.topic_id = T1.topic_id
            And T2.poster_id = $user_id
            And T2.post_status = 0
Where T2.topic_id Is Null
ORDER BY T1.post_time DESC

Answer 2

我不太确定您的要求是什么，但是通过查看您的查询，我认为这应该足够了。

SELECT DISTINCT(topic_id) 
FROM bb_posts 
WHERE poster_id <> $user_id OR post_status <> 0 
ORDER BY post_time DESC