一下SQL语句有什么有关问题

一下SQL语句有什么问题？
select @receiveNum=@receiveNum+Count(*)
  from (
select distinct(ProcessId)
from dbo.ProcessedInstance
where ApprovalOrgId=@orgId and AcceptanceTime>@stime and AcceptanceTime<@etime
)

对sql不熟

[解决办法]
select @receiveNum=@receiveNum+Count(*)
from (
select distinct(ProcessId)
from dbo.ProcessedInstance
where ApprovalOrgId=@orgId and AcceptanceTime>@stime and AcceptanceTime<@etime
) t
[解决办法]

SQL code

select @receiveNum=@receiveNum+Count(*)  from (select distinct(ProcessId)from dbo.ProcessedInstancewhere ApprovalOrgId=@orgId and AcceptanceTime>@stime and AcceptanceTime<@etime) t你是吧你面的查询语句作为表来查询，所以得去个别名t