SQL Server 中的if.else.构造

use yuyongTest

--exists:如果查询语句返回至少一行数据则返回true,否则返回false

if exists(select* from student where number=(-1))

 print('Y');

else

 print('N');

if exists(select* from student where number>=(-1))

 print('Y');

else

 print('N');