mysql子查询中的多个字段

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。我该怎么做呢？

我看过类似的帖子，但不能把它应用到我的帖子上。

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

实际上，我会再次重复子查询

Answer 2

也许像这样的东西可以帮助你：

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

但是如果没有表的结构，这是很困难的。

祝好运。