Question

SELECT 
  (SELECT date FROM forums WHERE topic_id=f.id OR id=f.id ORDER BY id DESC LIMIT 1) as last_reply, 
  f.*, p.id as pid, p.name FROM forums f 
      INNER JOIN players p ON p.id = f.author 
  WHERE f.topic_id=0 ORDER BY f.id DESC

在子查询中，我不仅要返回date字段，还要返回author字段。我怎么能这样做？

看了一下类似的帖子，但不能将它应用到我的。

Answer 1

我会这样做：

SELECT 
  (SELECT date FROM forums WHERE topic_id=f.id OR id=f.id ORDER BY id DESC LIMIT 1) as last_reply,
  (SELECT author FROM forums WHERE topic_id=f.id OR id=f.id ORDER BY id DESC LIMIT 1) as last_author,
  f.*, p.id as pid, p.name FROM forums f 
      INNER JOIN players p ON p.id = f.author 
  WHERE f.topic_id=0 ORDER BY f.id DESC

我实际上会再次重复子查询

Answer 2

也许这样的事情可以帮到你：

SELECT MAX(f.date), f.author
FROM forums f
    INNER JOIN players p ON
        p.id = f.author
WHERE f.tpoic_id = 0
GROUP BY f.author
ORDER BY f.id DESC

但没有桌子结构很难。

祝你好运。

mysql来自子查询的多个字段

2 个答案: