SQL Server查询子查询

Question

我有以下SQL

set @ID = '323232' 

select 
    tt.ItemOrder, tt.DisplayVal, 
    ActualDate = (select mfdate from mfseries where Id = @ID) 
from 
    tblTime tt 

有没有一种方法来简化这个查询不使用子查询？

Answer 1

DECLARE @date datetime 

select @date = mfdate from mfseries where Id = @ID 

select tt.ItemOrder,tt.DisplayVal,@date As ActualDate 
from tblTime tt