Mysql select count on left join with condition not working 条件不工作

Question

我需要计算左表上的记录数，我阅读了其他问题并以这个查询结束，但忽略了 COUNT 条件

SELECT  a.name, COUNT( f.status <> 'e' ) AS total               
FROM    album AS a LEFT JOIN photo AS f
        ON a.id = f.idalbum
WHERE   a.iduser = 4
GROUP   BY a.id

是 MySQL 5 数据库

Answer 1

您不能在 COUNT 语句中指定条件。

试试这个

   SELECT  a.name, COUNT( f.status  ) AS total               
   FROM    album AS a LEFT JOIN photo AS f
    ON a.id = f.idalbum
   WHERE   a.iduser = 4 or f.status <> 'e'
   GROUP   BY a.id