TSQL 备忘

基本控制语句：

--    1、if
declare @i int
set @i=3 
if @i=2 
    select 'x'
else
    select 'y'

--    2、while
declare @i int
set @i=5
while @i>0
begin
    if @i=2
        break
    select @i
    set @i=@i-1
end

--    3、case when
declare @i int
set @i=4
select 
case
 when @i=3 then '三' 
 when @i=4 then '四'
end 

declare @i int
set @i=3
select 
case when @i=3 then '三' else 'x' end,
case when @i=4 then '四' else 'y' end 

常用内置过程

--建表
CREATE TABLE [dbo].[person](    --编号，姓名，性别，生日，年龄，分派次数，是否党员，备注
    [cCode] [nvarchar](3) NOT NULL check(len(cCode)=3) primary key,
    [cName] [nvarchar](2) NOT NULL,
    [cGender] [nvarchar](1) NOT NULL check([cGender]='男' or [cGender]='女'),
    [dBirthday] [datetime] NULL    check([dBirthday]>'1960-01-01' and [dBirthday] <'1990-01-01'),
    [age] as datediff(yyyy,[dBirthday],getdate()),
    [iDispatchCount] [int] NULL,
    [bParty] [bit] NULL,
    [cMemo] [nvarchar](100) NULL
)
insert into person(cCode,cName,cGender,dBirthday,iDispatchCount)
select '001','小a','男','1980-01-01',3 union
select '002','小b','女','1973-03-17',0 union
select '003','小c','女','1970-10-04',10 union
select '004','小d','男','1985-12-12',0 union
select '005','小e','女','1981-02-23',5 union
select '006','小f','男','1982-03-04',7
 
--1、存储过程
--无返回值
create procedure pro1 @code nvarchar(10)
as
select * from person where cCode=@code

exec pro1 '003'

--有返回值
CREATE PROCEDURE myProc
@outparm      int      OUTPUT,
@inparm      int
AS
begin
SELECT @outparm = COUNT (*) FROM person WHERE iDispatchCount > @inparm
IF (@outparm > 0)
    RETURN 10000
ELSE
    RETURN -1
end
   
declare @iOutput int
declare @iReturn int
exec @iReturn=myProc @iOutput output,3
select @iOutput
select @iReturn


--2、函数
create  function myAdd(@i as int,@j as int) returns int
as
begin
    return @i+@j
end
select dbo.myAdd(2,4)


create  function Fun1() 
returns table
as
    return (select * from person)
select * from  dbo.Fun1()

--3、触发器
create trigger myTri1
on person
for update
as
begin
    declare @i nvarchar(10)
    declare @j int
    select @i=iDispatchCount from deleted
    select @j=iDispatchCount from inserted
    print '字段iDispatchCount从' + str(@i) + '变成' + str(@j)
end
   
update person set iDispatchCount=8 where cCode='001' 

--4、游标

一些应用：

批量生成测试数据

DECLARE @i INT
SET @i=1
WHILE @i<=3000
BEGIN
    PRINT @i
    INSERT INTO POOrder(code, date) VALUES(@i, Dateadd(day,@i%1000,getdate()));  
    SET @i=@i+1
END