Question

我有两个表pdc和class

select roll_no as roll,sum(pdc.amount) as amount,count(amount) as given,
       stu_profile.name,f_name,scholarship,class_id,batch_id,statuss 
from stu_profile left join 
     pdc 
     on pdc.roll=stu_profile.roll_no 
where 1 and class_id!='' and given=0 
group by roll

我想要一个计数（金额）栏的条件

Answer 1

使用having子句

 . . .
having count(amount) = 0;

Answer 2

然后回答你的问题是having条款。但是，您的查询格式错误，无法在大多数数据库中运行，包括更新版本的MySQL。

解决方案很简单：在聚合查询中，SELECT中的唯一列应该是GROUP BY密钥或聚合函数的参数。

让我假设你想要：

select p.roll_no as roll, sum(pdc.amount) as amount,
       count(pdc.amount) as given,
       p.name, p.f_name, p.scholarship, p.class_id, p.batch_id, p.statuss
from stu_profile p left join 
     pdc 
     on pdc.roll = p.roll_no 
where 1 and class_id <> '' 
group by roll, p.name, p.f_name, p.scholarship, p.class_id, p.batch_id, p.statuss

然后你可以添加如下内容：

having given = 0

计数列的where子句

2 个答案: