UC知道SQL,ALL问题,急急急!!
来源：百度知道 编辑：UC知道 时间：2024/05/04 22:20:46
select DeptNum,Instname,DeptName,count(AcNum)
from Department NATURAL JOIN Academic
group by DeptNum,Instname,DeptName
having count(AcNum)>=all
(select count(AcNum)
from Academic);
请问为什么会返回no rows selected,但是这是不可能的!
from Department NATURAL JOIN Academic
group by DeptNum,Instname,DeptName
having count(AcNum)>=all
(select count(AcNum)
from Academic);
请问为什么会返回no rows selected,但是这是不可能的!
给数据库加上别名看看 Department as depart Academic as acade 具体某个数据库里的字段用别名加点 例如 depart.DeptNum count(AcNum)也要加as 去数据库里运行下 看看出什么错误
JOIN是连接吧 应该后面有条件 on 你这里也没有
select DeptNum,Instname,DeptName,count(AcNum)
from Department NATURAL JOIN Academic
group by DeptNum,Instname,DeptName
你运行这个看就知道了
JOIN Academic on (?=?)