基本SQL排序依據查詢

Question

下面的查詢工作正常，並返回正確的結果，因爲我需要

select top 1 SID from vSTable where (ID in 
(select ID from Engine where Name='nnn' OR Name='mmm') 
and QuestionTypeID=1 and IsOfficial=1) order by vSTable.ITime desc; 

但是當我使用它像這樣

declare @SVal as int 

set @SVal = select top 1 SID 
      from vSTable 
      where (
       ID in 
        (select ID from Engine where Name='nnn' OR Name='mmm') 
       and QuestionTypeID=1 
       and IsOfficial=1 
      ) order by vSTable.ITime desc; 

我靠近選擇語句

錯誤不正確的語法

Answer 1

將括號中的select語句包裝起來

declare @SVal as int 

set @SVal = (select top 1 SID 
      from vSTable 
      where (
       ID in 
        (select ID from Engine where Name='nnn' OR Name='mmm') 
       and QuestionTypeID=1 
       and IsOfficial=1 
      ) order by vSTable.ITime desc); 

Answer 2

您的語法有點不合適。這應該工作：

select @SVal = (select top 1 SID from vSTable where (ID in 
    (select ID from Engine where Name='nnn' OR Name='mmm') 
    and QuestionTypeID=1 and IsOfficial=1) order by vSTable.ITime desc) 

請注意，您可以使用SET或SELECT進行該分配。