sql - 基本 SQL OrderBy 查询

Question

下面的查询工作正常，并根据我的需要返回正确的结果

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;

但是当我这样使用它时

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; 

我在 select stmt 附近收到错误的语法错误

Answer 1

将 select 语句括在括号中

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

你的语法有点不对劲。这应该有效：

  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)

请注意，您可以使用 SET 或 SELECT 进行该分配。