sql;"> --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)

sql;"> 　　--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

sql;"> --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

sql;"> --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,[State] nvarchar 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 #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,[ 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

sql;"> --while循环计算1到100的和 declare @a int declare @ sum int set @a=1 set @ sum =0 while @a<=100 begin set @ sum +=@a set @a+=1 end print @ sum

sql;"> --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

sql;"> declare @ID int declare @Oid int declare @Login varchar (50)

--定义一个游标
declare user_cur cursor for select ID,[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

sql;"> declare @ID int declare @Oid int declare @Login varchar (50)

--定义一个游标
declare user_cur cursor for select ID,@Login
print @ID
--print @Login
end
close user_cur
--摧毁游标
deallocate user_cur

sql;"> --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

sql;"> --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 =@a+@b END

--创建Return返回值存储过程
CREATE PROCEDURE PR_Sum2
@a int,@b int
AS
BEGIN
Return @a+@b
END

--执行存储过程获取output型返回值
declare @mysum int
execute PR_Sum 1,@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

sql;"> --新建标量值函数 create function FUNC_Sum1 ( @a int,@b int ) returns int as begin return @a+@b 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,[State] nvarchar 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