Question

I am trying to count the number of messages userid = 1 did and then COUNT the number of messages of all the other userid and print out the names of the people where the number of messages = the number of messages userid = 1 has.

因此,我需要做一个nes计。我有2个表格。信息和用户。

例如:

SELECT COUNT(*)
FROM MESSAGES
WHERE user_id = 1

And the result is 2. Then I need

SELECT COUNT(*)
FROM MESSAGES
WHERE COUNT(*) = 2

我如何为此nes计,以便我能够做这样的事情。

SELECT USER.user_name
FROM MESSAGES INNER JOIN USER ON MESSAGES.user_id = USER.user_id
WHERE COUNT(*) = (    
SELECT COUNT(*)
FROM MESSAGES
WHERE user_id = 1
)

以上例子对我不利。我正在使用Access女士。任何帮助都将受到赞赏。谢谢。

Answer 1

使用<代码>HAVING条

SELECT USER.user_name
FROM MESSAGES INNER JOIN USER ON MESSAGES.user_id = USER.user_id
GROUP BY MESSAGES.user_id, USER.user_name
HAVING COUNT(*) = (    
SELECT COUNT(*)
FROM MESSAGES
WHERE user_id = 1
)

友情链接