Question

我正在努力想出这个。我想做的是这样：

select [fields],
       ((select <criteria>) return 0 if no rows returned, return 1 if any rows returned) as SubqueryResult
where a=b

这可能吗？

Answer 1

请尝试：

select [fields],
       case when (select COUNT(*) from YourTable with criteria)>0 then 
            1 
       else 
            0 
       end 
       as SubqueryResult
where a=b

Answer 2

在T-sql中，您可以将给定要求的Exists子句用作：

select [fields],
       case when exists (select <criteria> from <tablename> ) then 1 
            else 0 
            end as SubqueryResult
from <tablename>     
where a=b

Answer 3

同样在TSQL中，您可以使用ISNULL()和SELECT TOP 1：

来完成

select [fields],
       ISNULL((SELECT TOP 1 1 FROM YourTable WHERE <criteria> ),0)
       as SubqueryResult
where a=b

使用EXISTS返回1或0作为子查询字段？

3 个答案: