导读:1建站知识sql不常用函数总结以及事务，增加，删除触发器，需要的朋友可以参考下网站建设多少钱如何seo优化推广网站。

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 ====================================================== 情况 case when xxx then xx when xxxx then xxxxx else end ======================================================= while xxx begin xxxxxx end 事务 ==============================================网站seo优化诊断工具===== begin tran declare @sum int = 0 update bank set balance=balance-1000 where cid='0001' set @sum=@sum+@@error update bank set balance=balance + 1000 where cid='0002' set @sum=@sum+@@error if @sum<>0 begin rollback print '回滚！' end else begin --提交事务 commit tran print '提交了！' end =================================================== begin tran begin try declare @sum int = 0 update bank set balance=balance-900 where cid='0001' set @sum=@sum+@@error update bank set balance=balance + 900 where cid='0002' set @sum=@sum+@@error commit end try begin catch rollback end catch ===================================================== declare @halfCount int= ceiling(@count/2.0) 向上 增加时触发器 ========================================= create trigger tri_TblClass_insert_after on TblClass after inse网站建设公司rt as begin declare @id int declare @name varchar(50) declseo网站优化培训are @desc varchar(50) select @id=tclassId,@name=tclassname,@desc=tclassdesc from inserted print @id print @name print @desc end ========================================= 删除时触发器 create trigger tri_TblClass_delete_after on TblClass instead of delete as begin insert into TblClassBak select * from deleted end ======================================== 作者 xhccom相关网站建设多少钱如何seo优化推广网站。

关键词标签: 函数 触发器