我从table1获取行:
SELECT table1.id, COUNT(commentTable1.id) AS CNT3, COUNT(photoTable1.id) AS CNT2, COUNT(fileTable1.id) AS CNT3 FROM table1
LEFT JOIN commentTable1 ON...
LEFT JOIN photoTable1 ON...
LEFT JOIN fileTable1 ON ...
如何正确地对每个 COUNT
使用 GROUP BY
?现在我得到了错误的 CNT3
最佳答案
您无法按计数分组,因此我假设您按 table1.id
分组
SELECT table1.id, COUNT(commentTable1.id) AS CNT3, COUNT(photoTable1.id) AS CNT2, COUNT(fileTable1.id) AS CNT3 FROM table1
LEFT JOIN commentTable1 ON...
LEFT JOIN photoTable1 ON...
LEFT JOIN fileTable1 ON ...
GROUP BY table1.id
关于mysql - 如何计算表中每一行的行数?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27463042/