一、定义变量
--简单赋值
declare @a int
set @a=5
print @a
--使用select语句赋值
declare @user1 nvarchar(50)
select @user1= ‘张三‘
print @user1
declare @user2 nvarchar(50)
select @user2 = Name from ST_User where ID=1
print @user2
--使用update语句赋值
declare @user3 nvarchar(50)
update ST_User set @user3 = Name where ID=1
print @user3
二、表、临时表、表变量
--创建临时表1
create 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_User1
drop 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
--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 #t
drop 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_User
select * 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
declare @a int
declare @ sum int
set @a=1
set @ sum =0
while @a<=100
begin
set @ sum [email protected]
set @a+=1
end
print @ sum
四、条件语句
--if,else条件分支
if(1+1=2)
begin
print ‘对‘
end
else
begin
print ‘错‘
end
--when then条件分支
declare @today int
declare @week nvarchar(3)
set @today=3
set @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‘
end
print @week
五、游标
declare @ID int
declare @Oid int
declare @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_cur
while @@fetch_status=0
begin
--读取游标
fetch next from user_cur into @ID,@Oid,@Login
print @ID
--print @Login
end
close user_cur
--摧毁游标
deallocate user_cur
六、触发器
--创建触发器
Create trigger User_OnUpdate
On ST_User
for Update
As
declare @msg nvarchar(50)
[email protected]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 output
AS
BEGIN
set @ sum [email protected][email protected]
END
--创建Return返回值存储过程
CREATE PROCEDURE PR_Sum2
@a int ,
@b int
AS
BEGIN
Return @[email protected]
END
--执行存储过程获取output型返回值
declare @mysum int
execute PR_Sum 1,2,@mysum output
print @mysum
--执行存储过程获取Return型返回值
declare @mysum2 int
execute @mysum2= PR_Sum2 1,2
print @mysum2
八、自定义函数
--新建标量值函数
create function FUNC_Sum1
(
@a int ,
@b int
)
returns int
as
begin
return @[email protected]
end
--新建内联表值函数
create function FUNC_UserTab_1
(
@myId int
)
returns table
as
return ( 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
)
as
begin
insert into @t select * from ST_User where ID<@myId
return
end
--调用表值函数
select * from dbo.FUNC_UserTab_1(15)
--调用标量值函数
declare @s int
set @s=dbo.FUNC_Sum1(100,50)
print @s
--删除标量值函数
drop function FUNC_Sum1