sql-server – 对select查询返回的行进行计数

发布时间：2020-12-12 16:10:40 所属栏目：MsSql教程来源：网络整理

导读：我需要计算以下查询返回的行数. select m.Company_idfrom Monitor as m inner join Monitor_Request as mr on mr.Company_ID=m.Company_id group by m.Company_id having COUNT(m.Monitor_id)=5 我已经尝试过跟随 select COUNT(*) from(select m.Company_idfr

我需要计算以下查询返回的行数.

select m.Company_id
from Monitor as m
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id
    group by m.Company_id
    having COUNT(m.Monitor_id)>=5

我已经尝试过跟随

select COUNT(*) from
(
select m.Company_id
from Monitor as m
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id
    group by m.Company_id
    having COUNT(m.Monitor_id)>=5)

它在查询分析器中提供了一个错误消息,其中说明如下：

Msg 102,Level 15,State 1,Line 7 Incorrect syntax near ‘)’.

解决方法

SQL Server需要您SELECT FROM或JOIN的子查询才能使用别名.

在您的子查询中添加一个别名(在本例中为x)：

select COUNT(*) from
(
select m.Company_id
from Monitor as m
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id
    group by m.Company_id
    having COUNT(m.Monitor_id)>=5)  x

（编辑：李大同）

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