Sql 如果没有“have”，如何按“count（*）`过滤INTEM？

我有一些疑问：

select disconnect_reason as disconnectReason, disconnect_cause, count(*) as callsCount 
from calls group by disconnect_reason, disconnect_cause 

如何仅获取callsCount=1的项目。

---

如果没有

having

，我如何获得它？

您始终可以使用

having

子句来筛选组，但如果您需要另一种方法，请尝试类似的方法

select * from 
(
select disconnect_reason as disconnectReason, disconnect_cause, count(*) as callsCount 
from calls group by disconnect_reason, disconnect_cause
) A
Where callsCount = 1

---

您始终可以使用

Having

子句来筛选组，但如果您需要另一种方法，请尝试以下方法

select * from 
(
select disconnect_reason as disconnectReason, disconnect_cause, count(*) as callsCount 
from calls group by disconnect_reason, disconnect_cause
) A
Where callsCount = 1

---

尝试将CTE用于MS SQL SERVER

with cte
as
(
select disconnect_reason as disconnectReason, disconnect_cause, count(*) as callsCount 
from calls group by disconnect_reason, disconnect_cause 
)
select * from cte where callsCount >0

---

尝试将CTE用于MS SQL SERVER

with cte
as
(
select disconnect_reason as disconnectReason, disconnect_cause, count(*) as callsCount 
from calls group by disconnect_reason, disconnect_cause 
)
select * from cte where callsCount >0

---

使用

have

有什么问题？在where子句中尝试子查询。使用

have

有什么问题？在where子句中尝试子查询。并非所有数据库引擎都支持此功能。OP没有指定他的。并非所有数据库引擎都支持此操作。OP没有具体说明他的身份。