--有输入参数的存储过程--create proc GetComment(@commentid int)asselect * from Comment where CommentID=@commentid --有输入与输出参数的存储过程--create proc GetCommentCount@newsid int,@count int outputasselect @count=count(*) from Comment where NewsID=@newsid --返回单个值的函数--create function MyFunction(@newsid int)returns intasbegindeclare @count intselect @count=count(*) from Comment where NewsID=@newsidreturn @countend --调用方法--declare @count intexec @count=MyFunction 2print @count --返回值为表的函数--Create function GetFunctionTable(@newsid int)returns tableasreturn(select * from Comment where NewsID=@newsid) --返回值为表的函数的调用--select * from GetFunctionTable(2)
SQLServer 存储过程中不拼接SQL字符串实现多条件查询
--以前拼接的写法 set @sql=' select * from table where 1=1 ' if (@addDate is not null) set @sql = @sql+' and addDate = '+ @addDate + ' ' if (@name <>'' and is not null) set @sql = @sql+ ' and name = ' + @name + ' ' exec(@sql)
下面是 不采用拼接SQL字符串实现多条件查询的解决方案
--第一种写法是 感觉代码有些冗余 if (@addDate is not null) and (@name <> '') select * from table where addDate = @addDate and name = @name else if (@addDate is not null) and (@name ='') select * from table where addDate = @addDate else if(@addDate is null) and (@name <> '') select * from table where and name = @name else if(@addDate is null) and (@name = '') select * from table --第二种写法是 select * from table where (addDate = @addDate or @addDate is null) and (name = @name or @name = '') --第三种写法是 SELECT * FROM table where addDate = CASE @addDate IS NULL THEN addDate ELSE @addDate END, name = CASE @name WHEN '' THEN name ELSE @name END
SQLSERVER存储过程基本语法
一、定义变量
--简单赋值declare @a intset @a=5print @a --使用select语句赋值declare @user1 nvarchar(50)select @user1= '张三'print @user1declare @user2 nvarchar(50)select @user2 = Name from ST_User where ID=1print @user2 --使用update语句赋值declare @user3 nvarchar(50)update ST_User set @user3 = Name where ID=1print @user3
二、表、临时表、表变量
--创建临时表1create table #DU_User1( [ID] [ int ] NOT NULL , [Oid] [ int ] NOT NULL , [Login] [nvarchar](50) NOT NULL , [Rtx] [nvarchar](4) NOT NULL , [ Name ] [nvarchar](5) NOT NULL , [ Password ] [nvarchar]( max ) NULL , [State] [nvarchar](8) NOT NULL);--向临时表1插入一条记录insert into #DU_User1 (ID,Oid,[Login],Rtx, Name ,[ Password ],State) values (100,2, 'LS' , '0000' , '临时' , '321' , '特殊' ); --从ST_User查询数据,填充至新生成的临时表select * into #DU_User2 from ST_User where ID<8 --查询并联合两临时表select * from #DU_User2 where ID<3 union select * from #DU_User1 --删除两临时表drop table #DU_User1drop table #DU_User2 --创建临时表CREATE TABLE #t( [ID] [ int ] NOT NULL , [Oid] [ int ] NOT NULL , [Login] [nvarchar](50) NOT NULL , [Rtx] [nvarchar](4) NOT NULL , [ Name ] [nvarchar](5) NOT NULL , [ Password ] [nvarchar]( max ) NULL , [State] [nvarchar](8) NOT NULL ,) --将查询结果集(多条数据)插入临时表insert into #t select * from ST_User--不能这样插入--select * into #t from dbo.ST_User --添加一列,为int型自增长子段alter table #t add [myid] int NOT NULL IDENTITY(1,1)--添加一列,默认填充全球唯一标识alter table #t add [myid1] uniqueidentifier NOT NULL default (newid()) select * from #tdrop table #t--给查询结果集增加自增长列 --无主键时:select IDENTITY( int ,1,1) as ID, Name ,[Login],[ Password ] into #t from ST_Userselect * from #t --有主键时:select ( select SUM (1) from ST_User where ID<= a.ID) as myID,* from ST_User a order by myID--定义表变量declare @t table( id int not null , msg nvarchar(50) null)insert into @t values (1, '1' )insert into @t values (2, '2' )select * from @t
三、循环
--while循环计算1到100的和declare @a intdeclare @ sum intset @a=1set @ sum =0while @a<=100begin set @ sum +=@a set @a+=1endprint @ sum
四、条件语句
--if,else条件分支if(1+1=2)begin print '对'endelsebegin print '错'end --when then条件分支declare @today intdeclare @week nvarchar(3)set @today=3set @week= case when @today=1 then '星期一' when @today=2 then '星期二' when @today=3 then '星期三' when @today=4 then '星期四' when @today=5 then '星期五' when @today=6 then '星期六' when @today=7 then '星期日' else '值错误'endprint @week
五、游标
declare @ID intdeclare @Oid intdeclare @Login varchar (50) --定义一个游标declare user_cur cursor for select ID,Oid,[Login] from ST_User--打开游标open user_curwhile @@fetch_status=0begin--读取游标 fetch next from user_cur into @ID,@Oid,@Login print @ID --print @Loginendclose user_cur--摧毁游标deallocate user_cur
五、游标
declare @ID intdeclare @Oid intdeclare @Login varchar (50) --定义一个游标declare user_cur cursor for select ID,Oid,[Login] from ST_User--打开游标open user_curwhile @@fetch_status=0begin--读取游标 fetch next from user_cur into @ID,@Oid,@Login print @ID --print @Loginendclose user_cur--摧毁游标deallocate user_cur
六、触发器
触发器中的临时表:
Inserted
存放进行insert和update 操作后的数据
Deleted
存放进行delete 和update操作前的数据
--创建触发器Create trigger User_OnUpdate On ST_User for Update As declare @msg nvarchar(50) --@msg记录修改情况 select @msg = N '姓名从“' + Deleted. Name + N '”修改为“' + Inserted. Name + '”' from Inserted,Deleted --插入日志表 insert into [LOG](MSG) values (@msg) --删除触发器drop trigger User_OnUpdate
七、存储过程
--创建带output参数的存储过程CREATE PROCEDURE PR_Sum @a int , @b int , @ sum int outputASBEGIN set @ sum =@a+@bEND --创建Return返回值存储过程CREATE PROCEDURE PR_Sum2 @a int , @b intASBEGIN Return @a+@bEND --执行存储过程获取output型返回值declare @mysum intexecute PR_Sum 1,2,@mysum outputprint @mysum --执行存储过程获取Return型返回值declare @mysum2 intexecute @mysum2= PR_Sum2 1,2print @mysum2
八、自定义函数
函数的分类:
1)标量值函数
2)表值函数
a:内联表值函数
b:多语句表值函数
3)系统函数
--新建标量值函数create function FUNC_Sum1( @a int , @b int)returns intasbegin return @a+@bend --新建内联表值函数create function FUNC_UserTab_1( @myId int)returns tableasreturn ( select * from ST_User where ID<@myId) --新建多语句表值函数create function FUNC_UserTab_2( @myId int)returns @t table( [ID] [ int ] NOT NULL , [Oid] [ int ] NOT NULL , [Login] [nvarchar](50) NOT NULL , [Rtx] [nvarchar](4) NOT NULL , [ Name ] [nvarchar](5) NOT NULL , [ Password ] [nvarchar]( max ) NULL , [State] [nvarchar](8) NOT NULL)asbegin insert into @t select * from ST_User where ID<@myId returnend --调用表值函数select * from dbo.FUNC_UserTab_1(15)--调用标量值函数declare @s intset @s=dbo.FUNC_Sum1(100,50)print @s --删除标量值函数drop function FUNC_Sum1
新闻热点
疑难解答