Question

我试试这个：

SELECT x.name 
FROM s x
WHERE (SELECT MAX(num) 
       FROM ((SELECT COUNT(*) AS num 
              FROM spj 
       WHERE n_post=x.n_post)>0) AS adf)

错误消息：

错误：“＆gt;
处或附近的语法错误
第2行：...... CT计数（*）为来自spj的数字，其中n_post = x.n_post）＆gt; 0）为adf ...

然后我试试这个：

SELECT x.name 
FROM s x
WHERE (SELECT MAX(num) 
       FROM ((SELECT COUNT(*) AS num 
              FROM spj 
              WHERE n_post=x.n_post)) AS adf)

错误消息：

ERROR: argument of WHERE must be type boolean, not type bigint LINE 2: where (select max(num) from ((SELECT count(*) as num from sp..

有什么问题？求你帮帮我。

THX。我的代码：

SELECT x.name 
FROM s x
WHERE (SELECT MAX(num) 
       FROM (SELECT COUNT(*) AS num 
              FROM spj 
       WHERE x.n_post=n_post) AS adf)>0

我需要n_post，它具有表spj中的最大条目数，但我不知道该怎么做。

Answer 1

如果您需要n_post，其中包含表spj中的最大条目数，请尝试使用此查询。这是MySQL查询，它使用LIMIT关键字。如果您使用MsSQL，则使用SELECT TOP 1而不是LIMIT 1。

SELECT x.name 
FROM s x
JOIN (SELECT n_post,COUNT(*) AS num FROM spj GROUP BY n_post) as y
     on x.n_post=y.n_post
ORDER BY y.num DESC 
LIMIT 1

PhpPgAdmin并选择（max（num）from（select count（*）as num ...）作为计数）

1 个答案: