sql不常用函数总结以及事务，增加，删除触发器 distinct 删除重复行 declare @x 申明一个变量 convert(varchar(20),tscore.tenglish) 类型转换 cast(xx as varchar(10)) 类型转换 @H_3010@www.jb51.cc @H3010@====================================================== 情况 @H3010@case @H3010@when xxx then xx @H3010@when xxxx then xxxxx @H3010@else @H3010@end ======================================================= while xxx @H3010@begin @H3010@xxxxxx @H3010@end @H3010@www.jb51.cc @H3010@事务 @H3010@=================================================== @H3010@begin tran @H3010@declare @sum int = 0 @H3010@update bank set balance=balance-1000 where cid='0001' @H3010@set @sum=@sum+@@error @H3010@update bank set balance=balance + 1000 where cid='0002' @H3010@set @sum=@sum+@@error if @sum<>0 @H3010@begin @H3010@rollback @H3010@print '回滚！' @H3010@end @H3010@else @H3010@begin @H3010@--提交事务 @H3010@commit tran @H3010@print '提交了！' @H3010@end @H3010@=================================================== @H3010@begin tran www.jb51.cc @H3010@begin try @H3010@declare @sum int = 0 @H3010@update bank set balance=balance-900 where cid='0001' @H3010@set @sum=@sum+@@error @H3010@update bank set balance=balance + 900 where cid='0002' @H3010@set @sum=@sum+@@error @H3010@commit @H3010@end try @H3010@begin catch @H3010@rollback @H3010@end catch @H301_0@===================================================== declare @halfCount int= ceiling(@count/2.0) 向上 增加时触发器 @H_3010@========================================= @H301_0@create trigger tri_TblClass_insertafter @H3010@on TblClass after insert @H3010@as @H3010@begin @H3010@declare @id int @H3010@declare @name varchar(50) @H3010@declare @desc varchar(50) @H3010@select @id=tclassId,@name=tclassname,@desc=tclassdesc from inserted print @id @H3010@print @name @H3010@print @desc @H3010@end www.jb51.cc @H301_0@========================================= 删除时触发器 @H_301_0@create trigger tri_TblClass_deleteafter @H3010@on TblClass instead of delete @H3010@as @H3010@begin insert into TblClassBak @H3010@select * from deleted @H3010@end @H3010@======================================== @H301_0@作者 xhccom