mysql - IFNULL() 可以使用 MySQL 返回列值为 int 的字符串吗？

Question

我的查询

select cname, count(screening_occapancy.idclient) as 'Count'
from client, screening_occapancy 
where client.client_no = screening_occapancy.idclient 
group by cname

返回以下内容:

Name        Count
Name1        2
Name2        3
Name3        6

等等，现在我希望如果值为 null 或 0，则“Count”中的值“未找到”，这可能吗？我的结果中需要类似的东西:

    Name        Count
    Name1         2
    Name2         3
    Name3    "Not found"

Answer 1

    Select cname , 
case when Count is null or count =0 then 'Not found' 
else Count end as count
 from
    (select cname,
 count(screening_occapancy.idclient) as 'Count' 
    from client left join screening_occapancy 
    on
    client.client_no = screening_occapancy.idclient group by cname) t

在查询上方写一个包装器查询以检查计数列