SQL基础系列(3)-变量、函数、存储过程等

 1 定义变量
 2 
 3 DECLARE @a INT
 4 
 5 赋值
 6 
 7 SET @a=1
 8 
 9 PRINT @a
10 
11 DECLARE @name NVARCHAR(30)
12 
13 --select 赋值
14 
15 SELECT @name=‘zcx‘
16 
17 PRINT @name
18 
19 SELECT @name=FirstName FROM dbo.Persons
20 
21 PRINT @name
22 
23  
24 
25 DECLARE @name NVARCHAR(50)
26 
27 --update 赋值
28 
29 UPDATE  Persons
30 
31 SET     @name = FirstName
32 
33 WHERE   ID = 1
34 
35 PRINT @name

 1 create table #persion
 2 
 3 (
 4 
 5      [id] [int]  NOT NULL,
 6 
 7      [name] [nvarchar](5) NOT NULL,
 8 
 9      [pwd] [nvarchar](20) NULL
10 
11 )
12 
13  
14 
15 insert into #persion values(1,‘zcx‘,‘123‘)
16 
17  
18 
19 SELECT * INTO #psersion1 FROM #persion
20 
21 select * from #persion UNION ALL select * from #psersion1
22 
23  
24 
25 DROP TABLE #persion
26 
27 DROP TABLE #psersion1

 1 declare @mytable table
 2 
 3 (
 4 
 5     id int not null,
 6 
 7     name nvarchar(50) null
 8 
 9 )
10 
11  
12 
13  
14 
15 INSERT INTO @mytable
16 
17         ( id, name )
18 
19 VALUES  ( 0, -- id - int
20 
21           N‘zcx‘  -- name - nvarchar(50)
22 
23           )
24 
25          INSERT INTO @mytable
26 
27                  ( id, name )
28 
29          VALUES  ( 0, -- id - int
30 
31                    N‘zjj‘  -- name - nvarchar(50)
32 
33                    )
34 
35  
36 
37 select * from @mytable

 1 DECLARE @index INT
 2 
 3 DECLARE @resukt INT
 4 
 5 SET @index = 1
 6 
 7 SET @resukt = 0
 8 
 9 WHILE @index <= 100
10 
11     BEGIN
12 
13         SET @resukt += @index
14 
15         SET @index += 1
16 
17     END
18 
19 PRINT @resukt

 1 IF ( 3 > 5 )
 2 
 3     BEGIN
 4 
 5         PRINT ‘true‘
 6 
 7     END
 8 
 9 ELSE
10 
11     BEGIN
12 
13         PRINT ‘false‘
14 
15     END
16 
17  
18 
19 When then
20 
21 DECLARE @num INT
22 
23 DECLARE @name NVARCHAR(30)
24 
25 SET @num = 3
26 
27 SET @name = CASE WHEN @num = 1 THEN ‘elephant‘
28 
29                  WHEN @num = 2 THEN ‘hippo‘
30 
31                  WHEN @num = 3 THEN ‘trigger‘
32 
33                  ELSE ‘false‘
34 
35             END
36 
37 PRINT @name

 1 OPEN mycursor
 2 
 3 WHILE @@FETCH_STATUS=0
 4 
 5 BEGIN
 6 
 7     FETCH NEXT FROM mycursor INTO @name
 8 
 9     PRINT @name
10 
11 END
12 
13 CLOSE mycursor
14 
15 --回收
16 
17 DEALLOCATE mycursor

 1 Create trigger persion_update
 2 
 3     On dbo.Persons
 4 
 5     for Update
 6 
 7 As
 8 
 9     declare @msg nvarchar(50)
10 
11     --@msg记录修改情况
12 
13     select @msg = N‘姓名从“‘ + Deleted.FirstName + N‘”修改为“‘ + Inserted.FirstName + ‘”‘ from Inserted,Deleted
14 
15     --插入日志表
16 
17     insert into TAB(Col2)values(@msg)

 1 DROP PROCEDURE compute_add
 2 
 3 CREATE PROCEDURE compute_add
 4 
 5     @p1 INT ,
 6 
 7     @p2 INT ,
 8 
 9     @p3 INT OUTPUT
10 
11 AS
12 
13     BEGIN
14 
15         SET @p3=@p1+@p2
16 
17     END
18 
19  
20 
21     DECLARE @result INT
22 
23     EXEC compute_add 1,2,@result OUTPUT
24 
25     PRINT @result

 1 CREATE FUNCTION COMPUTE_ADD ( @p1 INT, @p2 INT )
 2 
 3 RETURNS INT
 4 
 5 AS
 6 
 7     BEGIN
 8 
 9         RETURN @p1+@p2
10 
11     END

 1 CREATE FUNCTION mytable ( @id INT )
 2 
 3 RETURNS TABLE
 4 
 5 AS
 6 
 7 RETURN
 8 
 9     ( SELECT    *
10 
11       FROM      dbo.Persons
12 
13       WHERE     id < @id
14 
15     )

 1 CREATE FUNCTION mytable ( @id INT )
 2 
 3 RETURNS @table TABLE
 4 
 5     (
 6 
 7       firstname NVARCHAR(50) ,
 8 
 9       lastname NVARCHAR(50)
10 
11     )
12 
13 AS
14 
15     BEGIN
16 
17         INSERT  INTO @table
18 
19                 SELECT  firstname ,
20 
21                         lastname
22 
23                 FROM    dbo.Persons
24 
25                 WHERE   id < @id
26 
27         RETURN
28 
29 END