小编vab*_*bii的帖子

我正在对变量进行简单的"选择"但不能理解第二个片段的输出.

按预期工作:

declare @tname as varchar(100) = 'F99Special_DMT';

select top(1) @tname = form_name 
from [dbo].[forms] 
where form_name > @tname

print @tname; -- output = F99Special_Physical

表格表格具有按form_name排序的行.F99Special_Physical是最后一行的值.

declare @tname as varchar(100) = 'F99Special_Physical';

select top(1) @tname = form_name 
from [dbo].[forms] 
where form_name > @tname

print @tname; -- output = F99Special_Physical

它不应该输出null吗？

谢谢.