Mysql 用了 having，怎么计算总数了。

• 请不要在回答技术问题时复制粘贴 AI 生成的内容

This topic created in 4389 days ago, the information mentioned may be changed or developed.

SELECT *,一个表达式 AS flag FROM (这里2个表INNER JOIN) AS c

INNER JOIN 表D AS d

ON c.part = d.part HAVING flag='1'

现在having之后是2条结果，我直接用 select count(*) xxxx 结果是4，不准确。

表达式

flag=

d.part

5 replies • 2014-06-20 15:58:19 +08:00

hennywei

Jun 20, 2014

group by 呢

qq2511296

Jun 20, 2014

select count(t.*) from (
SELECT *,一个表达式 AS flag FROM (这里2个表INNER JOIN) AS c

INNER JOIN 表D AS d

ON c.part = d.part HAVING flag='1'
) t

楼主这样测试结果是4？

HAVING好像是最后才执行一般都是放在group by 后面的

coolicer

Jun 20, 2014

@qq2511296 我测试了是放后面才行。我直接在前端算长度了就知道总数，毕竟不多。

F281M6Dh8DXpD1g2

Jun 20, 2014

没看懂什么意思,lz不妨贴个例子?

coolicer

Jun 20, 2014

@qq2511296 刚才没看清你的例子，我没有试。

@liprais 目测2楼的应该可以