SQLServer学习笔记系列12

一.写在前面的话

这个sql学习系列，今天准备告一段落，虽然短短的十几篇文章，深刻感受到将学习的东西记录下来，是需要一种坚持！

这些东西只有反复的学习吸收，最终沉淀下来的才是属于自己的知识。也是提醒自己，今后的日子更要有计划，转眼又是7月份了，

时间不等人，岁月不饶人！坚持自己的计划，坚持向往的东西，踏实学习，因为自己不会的还太多，那些大牛还在学习，

我就更没理由逃避！也希望结交一些朋友，一起讨论技术，一起学习，一起进步！

 

二.触发器

触发器是一种特殊类型的存储过程，不能被显示的执行。它所监控的是对某一个表的操作，然后对应的执行相应的sql语句。

常见的触发器有三种：分别应用于Insert , Update , Delete 事件。触发器没有参数。 分为：after触发器instead of 触发器。

实例:审核货运公司表，表发生了操作以后，记录日志。用触发器监控。

1.创建日志表，记录对货运公司的操作：

 USE TSQLFundamentals2008;
  IF OBJECT_ID('shipper_log') IS NOT NULL
  DROP TABLE shipper_log;
  CREATE TABLE shiiper_log
  (
  logId INT IDENTITY(,) PRIMARY KEY,
  opdate  datetime DEFAULT GETDATE(),
  opuser nvarchar(),
  op nvarchar(),
  shipname nvarchar(),
  shipphone nvarchar()
  )

2.创建审核货运公司的触发器：

 CREATE TRIGGER tg_ship
 ON  sales.shippers AFTER INSERT ,DELETE,UPDATE
 as
 INSERT INTO dbo.shiiper_log
         ( opdate ,
           opuser ,
           op ,
           shipname ,
           shipphone
         )
 SELECT GETDATE() , -- opdate - datetime
           CURRENT_USER , -- opuser - nvarchar()
           N'插入' , -- op - nvarchar()
           companyname, -- shipname - nvarchar()
          phone  -- shipphone - nvarchar()
         FROM INSERTED;

3.创建完成触发器以后，我们可以查看一下记录货运公司日志表里面的内容：

 SELECT * FROM dbo.shiiper_log;

可以看到数据为空，当我们向货运公司插入一条记录如何了？

 INSERT INTO Sales.Shippers
         ( companyname, phone )
 VALUES  ( N'Isoftstone', -- companyname - nvarchar()
           N''  -- phone - nvarchar()
           )

插入以后，我们再查看一下多货运公司操作的记录表：

 SELECT * FROM dbo.shiiper_log;

我们看到插入一条记录以后，执行消息里面受影响行数有两条：

我们继续查询下日志表记录：

 SELECT * FROM dbo.shiiper_log;

这就实现了对货运公司操作的监控，从日志表里面就可以看到货运公司表里面操作的记录。

三.获取标识问题

标识列有利于相当于一个特殊标记，我们可以根据标识列很容易的去查看数据。

（1）获取系统提供的标识值，整个系统范围内。

 INSERT INTO Sales.Shippers
         ( companyname, phone )
 VALUES  ( N'Isoftstone', -- companyname - nvarchar()
           N''  -- phone - nvarchar()
           )

           --整个系统范围内
           SELECT @@IDENTITY;

我们先向货运公司表里面插入一条记录，然后查询系统的标识值，由于货运公司表做了触发器处理，所以插入一条记录时候，同时向货运公司

日志表里面也插入了一条记录。所以我们在查询系统当前的标识值时，查询到的是最新的系统范围内的标识值。

（2）获取当前作用域中最新的的标识值。

           --当前作用域内最新的标识值
           SELECT SCOPE_IDENTITY();

通过查询货运公司表可以看到当前作用域内最大的标识值为8.

这个学习系列写完，让自己也学会了很多，知道做一件事情坚持下去，才会让自己成长！

脚踏实地，一步一步踏踏实实走下去，相信越努力越幸运！后续会继续学习，

永远相信美好的事情即将发生！希望各位大牛给出指导，不当之处虚心接受学习！谢谢！

这里分享下这个系列所写的sql脚本。

select top  * from A where ID
not in(select top  ID from A  order by ID asc)
order by ID asc

select top  * fron A where ID>
(select Max(ID) from (select top  ID from A order by ID)as t)
order by ID asc

select top  * from A a1
WHERE NOT EXISTS
(SELECT * from
(SELECT TOP  * FROM A ORDER BY id asc) a2
WHERE a2.id =a1.id
)

select top() percent * from hr.employees  

select count(*) as N'总人数' from hr.employees

select top  with ties orderid,orderdate
from sales.orders order by orderdate  desc

select firstname,lastname ,count(*) over()  as N'总人数'
from hr.employees

select orderid,custid,sum(val) over (partition by custid) as N'顾客消费总额',
sum(val) over() as N'订单总额' from sales.ordervalues

select country,ntile() over (order by country) as N'ntile分组',dense_rank() over(order by country) as N'dense_rank排名', lastname,firstname
from hr.employees
order by country

select lastname,firstname,country,row_number() over( partition by country order by country) as N'排名'
from hr.employees

select * from sales.ordervalues
where val>= and val<=

select * from sales.ordervalues
where val between  and 

select * from sales.ordervalues
where custid= or custid= or custid=

select * from sales.ordervalues
where custid in(,,)

 select * from Hr.employees
 where lastname like '%a%'

 declare @t char();
 set @t='hello';
 set @t=isnull(@t,'')+'world';
 print datalength(rtrim(@t)

 select productname,replace(productname,'Product','产品名')
 from production.products

 select productname,stuff(productname,,,'::::')
 from production.products

  select productname,upper(productname),lower(productname)
 from production.products

 declare @s char();
 set @s='hello';
 select  datalength(rtrim(@s));
 print len(@s);

 select firstname,lastname,
 case region
 when 'WA' then '华盛顿地区'
 else '其他地区'
 end
 from hr.employees

 select firstname,lastname,region
 from hr.employees

 select firstname,lastname,
 case when region ='WA' then '华盛顿地区'
      when region is null then '未知地区'
 else '其他地区'
 end
 from hr.employees

 select * from sales.orders
 where orderdate>''

 select * from sales.orders
 where orderdate>cast('' as datetime)

 select datepart(year,getdate()) as N'年份',
        datepart(month,getdate()) as N'月份',
        datepart(day,getdate()) as N'日',
        datepart(hour,getdate()) as N'时',
        datepart(minute,getdate()) as N'分',
        datepart(second,getdate()) as N'秒'

  select datepart(dayofyear,getdate()) as N'一年中的第几天',
        datepart(weekday,getdate()) as N'一星期中第几天',
        datepart(week,getdate()) as N'今年的第几周'

 select dateadd(day,,getdate()) as N'20天后的是什么日子',
        datediff(year,'',getdate()) as N'祖国成立这么多年啦',
        datediff(year,'',getdate()) as N'屌丝多大啦'

 select convert(nvarchar,getdate(),) as N'转化后的形式',
       left( convert(nvarchar,getdate(),),) as N'取出年月'

 select orderid,custid,empid from sales.orders

 select * from hr.employees;
 select * from sales.shippers;

 select a.*,b.*
 from hr.employees a cross join sales.shippers b;

 select * from production.categories
 select * from production.products 

 select a.categoryid,a.categoryname,b.productid,b.productname
 from production.categories a inner join production.products b
 on a.categoryid=b.categoryid;

 select * from sales.customers
 select * from sales.orders

 select  a.custid,b.custid,a.contactname,a.fax,
        count(b.orderid) as N'顾客订单数量'
 from sales.orders b right join sales.customers a
 on a.custid=b.custid
 group by a.custid ,a.fax,a.contactname,b.custid
 order by count(b.custid);

 select distinct orderdate,count(*) as N'每日订单量' from sales.orders
 where orderdate between '' and ''
 group by orderdate

 create table nums
 (
   n int
 );

 select * from nums;

 declare @i int;
 set @i=;
 while @i<
 begin
 set @i=@i+;
 insert into nums(n) values(@i);
 end

 select dateadd(day,f.n,''),count(orderid) as N'每日订单数量'
 from nums f  left join sales.orders m on
  dateadd(day,f.n,'')= m.orderdate
  group by dateadd(day,f.n,'')
  order by dateadd(day,f.n,'')

  select birthdate,lastname
  from hr.employees
  where birthdate=
  (
      select max(birthdate)
      from hr.employees
  )

  select * from Sales.OrderValues

  select custid,contactname,country
  from sales.customers where custid=
  (
              select custid from Sales.OrderValues
              where val=
            (
              select max(val) as N'最贵订单'
               from Sales.OrderValues
             )
  )

  select * from sales.customers

  SELECT distinct country from  sales.customers
  where country not in
  (
  select  country from production.suppliers
  )

  select custid, count(*) as N'订单数量' from sales.orders
  group by custid order by custid

  select distinct custid,count(*)  over (partition by custid) as N'订单数量'
  from sales.orders

  select n.custid,n.contactname,
  (
  select count(*)
  from sales.orders m
  where m.custid=n.custid
  ) as N'订单数量'
  from sales.customers n

  select distinct m.country from sales.customers m
  where  not exists
  (
      select n.country from production.suppliers n
      where   n.country= m.country
  )

  select distinct
  (
     select max(custid) from
     sales.orders m where m.custid< n.custid
  ) as N'前一个订单',n.custid as N'当前订单',
    (
     select min(custid) from
     sales.orders p where p.custid> n.custid
  ) as N'后一个订单'
  from sales.orders n

select n.orderyear,
(
   select sum(qty)
   from  Sales.OrderTotalsByYear  m
   where m.orderyear<=n.orderyear
) as N'累计订单数量'
 from  Sales.OrderTotalsByYear n
 order by n.orderyear;

 SELECT * FROM
 (
 SELECT custid,COUNT(*) OVER(PARTITION BY country)
 FROM Sales.Customers
 ) t(custid,顾客数量)

 DECLARE @country NVARCHAR();
 SET @country='UK';
 WITH USE_Customers(公司名,国家名)
 AS
 (
   SELECT companyname ,country
   FROM Sales.Customers
   WHERE country=@country
 )

 SELECT * FROM USE_Customers

 SELECT YEAR(orderdate) AS N'年度',custid,COUNT(*) AS N'订单数量'
 FROM Sales.Orders
 GROUP BY YEAR(orderdate),custid
 HAVING COUNT(*) >;

 --()
 SELECT  YEAR(orderdate) AS orderyear,custid
 FROM Sales.Orders

 --()
 SELECT orderyear,custid,COUNT(*) AS N'订单数量'
 FROM
 (
     SELECT  YEAR(orderdate) AS orderyear,custid
     FROM Sales.Orders
 ) AS t1
 GROUP BY orderyear,custid

 --()
 SELECT orderyear,custid,ordercount
 FROM
 (
 SELECT orderyear,custid,COUNT(*) AS  ordercount
 FROM
         (
             SELECT  YEAR(orderdate) AS orderyear,custid
             FROM Sales.Orders
         ) AS t1
         GROUP BY orderyear,custid
 ) AS t2
 WHERE ordercount >

 WITH yearorder01
 AS
 (
       SELECT YEAR(orderdate) AS orderyear,custid
       FROM Sales.Orders
 ),
 yearorder02
 AS
 (
         SELECT orderyear,custid,COUNT(*) AS ordercount
         FROM yearorder01
         GROUP BY orderyear,custid
 ),
 yearorder03
 AS
 (
        SELECT orderyear,custid,ordercount
        FROM yearorder02
        WHERE  ordercount>
 )

 SELECT * FROM yearorder03

 SELECT pre_orderyear,now_orderyear,pre_custcount,now_custcount,
       (now_custcount-pre_custcount) AS N'顾客数量差'
 FROM
 (
 SELECT YEAR(orderdate) AS now_orderyear,COUNT(DISTINCT custid) AS now_custcount
 FROM Sales.Orders
 GROUP BY YEAR(orderdate)
 ) AS t1
 LEFT JOIN
 (
  SELECT YEAR(orderdate) AS pre_orderyear,COUNT(DISTINCT custid) AS  pre_custcount
 FROM Sales.Orders
 GROUP BY YEAR(orderdate)
 ) AS t2
 ON t1.now_orderyear=t2.pre_orderyear+;

 WITH custcount
 AS
 (
 SELECT YEAR(orderdate) AS orderyear,COUNT(DISTINCT custid) AS  custcount
 FROM Sales.Orders
 GROUP BY YEAR(orderdate)
 )

 SELECT t1.orderyear AS nowYear,t2.orderyear AS preYear,t1.custcount AS nowcount,t2.custcount AS precount,
       (t1.custcount-t2.custcount) AS N'顾客数量差'
 FROM custcount t1
 LEFT JOIN  custcount t2
 ON t1.orderyear=t2.orderyear+;

 SELECT t1.empid,t1.mgrid,t1.lastname,t2.empid,t2.lastname
 FROM HR.Employees t1 LEFT JOIN hr.Employees t2
 ON t1.mgrid =t2.empid

 SELECT * FROM HR.Employees
 WHERE mgrid in
 (SELECT empid FROM
 hr.Employees WHERE mgrid=
 ) 

DECLARE @mgrid INT;
SET @mgrid=;
WITH Emplist
AS
(
    --此处为起点，执行一次
    SELECT empid,lastname,mgrid
    FROM HR.Employees
    WHERE mgrid=@mgrid
    UNION ALL

    --递归开始

    SELECT e.empid,e.lastname,e.mgrid
    FROM HR.Employees e INNER JOIN Emplist m
    ON e.mgrid=m.empid 

)

SELECT * FROM Emplist

CREATE VIEW USA_cusomers
AS
(
   SELECT * FROM
   sales.customers
   WHERE country='USA'
)

SELECT custid,country FROM dbo.USA_cusomers;
DROP VIEW dbo.USA_cusomers;

SELECT country
FROM Sales.Customers
UNION
SELECT country
FROM hr.Employees;

SELECT country
FROM Sales.Customers
intersect
SELECT country
FROM hr.Employees;

SELECT country
FROM Sales.Customers
EXCEPT
SELECT country
FROM hr.Employees;

IF OBJECT_ID('dbo.orders','U') IS NOT NULL
DROP TABLE dbo.orders;
CREATE TABLE dbo.orders
(
   orderid int NOT NULL  PRIMARY KEY,
   empid int NOT NULL,
   custid int NOT NULL,
   orderdate datetime,
   qty int
);

INSERT INTO dbo.orders(orderid,empid,custid,orderdate,qty)
VALUES (,,,'',),
       (,,,'',),
        (,,,'',),
        (,,,'',),
        (,,,'',),
        (,,,'',),
        (,,,'',),
        (,,,'',)

SELECT * FROM dbo.orders

SELECT empid,SUM(qty) AS N'顾客消费金额'
FROM dbo.orders
GROUP BY empid;

SELECT empid,
SUM(CASE when empid= THEN qty end) AS N'2号顾客消费金额',
SUM(CASE when empid=3THEN qty end) AS N'3号顾客消费金额',
SUM(CASE when empid= THEN qty end) AS N'4号顾客消费金额',
SUM(CASE when empid= THEN qty end) AS N'5号顾客消费金额',
SUM(CASE when empid= THEN qty end) AS N'6号顾客消费金额'
FROM dbo.orders
GROUP BY empid;

SELECT empid,[],[],[],[],[]
FROM
(
    --只返回pivot中用到的列
   SELECT empid,qty,custid
   FROM dbo.orders
) AS t
PIVOT (
     SUM(t.qty) FOR t.custid IN ([],[],[],[],[])--做列名称
) AS P

USE TSQLFundamentals2008;

SELECT * FROM sales.Shippers

INSERT INTO Sales.Shippers
        ( companyname, phone )
VALUES  ( N'顺风', -- companyname - nvarchar()
          N''  -- phone - nvarchar()
          ),
          (N'申通',
           N''),
           (
           N'中通',
           N''
           )

          DELETE FROM Sales.Shippers WHERE shipperid=

       SELECT * FROM sales.Shippers   

       BEGIN TRANSACTION;

        DELETE FROM Sales.Shippers WHERE shipperid=;
        DELETE FROM Sales.Shippers WHERE shipperid=;

        COMMIT;

       BEGIN TRANSACTION;

        UPDATE  Sales.Shippers SET companyname='abc' WHERE shipperid=;
        UPDATE  Sales.Shippers SET companyname='XYZ' WHERE shipperid=;

        COMMIT;
         KILL 

USE TSQLFundamentals2008;

BEGIN TRANSACTION;

UPDATE Production.Products
SET unitprice=unitprice+
WHERE productid=;

--TSQL编程
--定义变量
DECLARE  @s INT;
SET @s=;
PRINT @s;

DECLARE @str NVARCHAR;
SET @str ='Hello World';
PRINT @str;

DECLARE @m NVARCHAR();
SELECT @m=;
PRINT @m;

DECLARE @sum INT;
SELECT @sum=COUNT(*) FROM Sales.Customers;
PRINT @sum;

DECLARE @mi DATETIME;
SET @mi=DATEPART(MINUTE,GETDATE());
IF(@mi>)
PRINT '该睡觉了！';
ELSE
PRINT '继续学习！'

DECLARE @sumadd int;
DECLARE @k INT;
SET @k=;
SET @sumadd=;
WHILE @k<
BEGIN
     SET @K=@K+;
     SET @sumadd=@sumadd+@k;
END
PRINT @sumadd;

SELECT  companyname
FROM  Sales.Customers;

DECLARE @name NVARCHAR();
SELECT @name=companyname
FROM Sales.Customers;
PRINT @name;

--.声明游标,基于查询
DECLARE c CURSOR
FOR
SELECT companyname
FROM Sales.Customers;

DECLARE @name NVARCHAR();

--.在使用时候,必须打开游标
OPEN c;

--.从游标中读取数据,每次可以读取出来一条数据
FETCH NEXT FROM c INTO @name;

--.注意fetch,并不一定能获得实际的数据
WHILE  @@fetch_status=
BEGIN
PRINT @name;
FETCH NEXT FROM c INTO @name;

END;

--.游标使用完成以后,一定要关闭
CLOSE c;

--.释放游标
DEALLOCATE c;

--存储过程
CREATE PROCEDURE ModifyPrice
(
  @num money

)
AS
UPDATE Production.Products
SET unitprice=unitprice+@num;

CREATE PROCEDURE GetCustomersCount
(
 @count int OUTPUT
)
AS
DECLARE  @num INT;
SELECT        @num=COUNT(*) FROM Sales.Customers;

--传出

SET @count=@num;
go

--必须使用变量来保存传出的参数
DECLARE @myCount int;

--前面是参数中定义的传出参数
--后面是我们定义的用来保存输出结果的变量

EXEC GetCustomersCount @count=@myCount OUTPUT;

PRINT @myCount;              

--创建用户
CREATE PROCEDURE CreateUser
(
   @username nvarchar()
)
AS
DECLARE @namelen INT;
SET @namelen=LEN(@username);

IF    @namelen>
RETURN
ELSE
RETURN  ;

GO
--定义变量保存结果

DECLARE @ReturnValue INT;
EXEC  @ReturnValue=dbo.CreateUser @username = N'liupeng'  -- nvarchar()
PRINT @ReturnValue;

--创建函数
CREATE FUNCTION Getminnutes
(
 @datevalue datetime  --传入参数
)
--函数可以直接返回一个值
RETURNS int
AS
begin
 --函数体
 DECLARE @mi INT;
 SET @mi=DATEPART(MINUTE,@datevalue);
 RETURN @mi;
 END;

SELECT dbo.Getminnutes(GETDATE())

--创建数据库testDB
if DB_ID('testDB') is not NULL
DROP DATABASE testDB;
CREATE DATABASE testDB ;
go
IF OBJECT_ID('testTable') IS NOT NULL
DROP TABLE testTable;
CREATE TABLE testTable
(
id INT IDENTITY(,) PRIMARY KEY NOT NULL,
userName NVARCHAR() NOT NULL,
userPWD  NVARCHAR() NOT NULL,
userPhone NVARCHAR() NOT NULL
)

go 

 --插入数据
 set identity_insert testTable on  --设置为on时，可以向标识列中插入
 declare @count int
 set @count=
 while @count<=
 begin
    insert into testTable(id,userName,userPWD,userPhone) values(@count,'liupeng','liupeng_IT','@liupengwuhan@gmail.com')
     set @count=@count+
end
set identity_insert testTable off

SELECT * FROM testTable

 create procedure proc_pagedFenye_with_selectMax  --利用select top and select max(列)
 (
     @pageIndex int,  --页索引
     @pageSize int    --页记录数
 )
 as
 begin
 set nocount on;
     declare @timediff datetime
   declare @sql nvarchar()
    select @timediff=Getdate()
    set @sql='select top '+str(@pageSize)+' * From testTable where(ID>(select max(id) From (select top '+str(@pageSize*@pageIndex)+' id From testTable order by ID) as TempTable)) order by ID'
   execute(@sql)
   select datediff(ms,@timediff,GetDate()) as 查询时间
set nocount off;
END

EXEC proc_pagedFenye_with_selectMax ,

create procedure proc_pagedFenye_with_notin  --利用select top and select not in
(
     @pageIndex int,  --页索引
     @pageSize int    --每页记录数
)
 as
 begin
    set nocount on;
    declare @timediff datetime --耗时
    declare @sql nvarchar()
    select @timediff=Getdate()
    set @sql='select top '+str(@pageSize)+' * from testTable where(ID not in(select top '+str(@pageSize*@pageIndex)+' id from testTable order by ID ASC)) order by ID'     execute(@sql)  --因select top后不支技直接接参数，所以写成了字符串@sql
    select datediff(ms,@timediff,GetDate()) as 查询时间
    set nocount off;
END

EXEC proc_pagedFenye_with_notin ,

create procedure proc_pagedFenye_with_Rownumber  --利用SQL 2005中的Row_number()
 (
    @pageIndex int,
    @pageSize int
 )
 as
 begin
 set nocount on;
    declare @timediff DATETIME;
    select @timediff=getdate()
    select * from (select *,Row_number() over(order by ID asc) as IDRank from testTable) as IDWithRowNumber where IDRank>@pageSize*(@pageIndex) and IDRank<@pageSize*(@pageIndex+)
    select  as 查询时间
set nocount off;
END

EXEC proc_pagedFenye_with_Rownumber ,

select * from (select *,Row_number() over(order by ID asc) as IDRank from testTable) as IDWithRowNumber where IDRank>*(-) and IDRank<*(+) 

SELECT* FROM testTable

USE TSQLFundamentals2008;
SET NOCOUNT ON;
SELECT TOP   *  FROM Sales.Customers

--触发器
USE TSQLFundamentals2008;
 IF OBJECT_ID('shipper_log') IS NOT NULL
 DROP TABLE shipper_log;
 CREATE TABLE shiiper_log
 (
 logId INT IDENTITY(,) PRIMARY KEY,
 opdate  datetime DEFAULT GETDATE(),
 opuser nvarchar(),
 op nvarchar(),
 shipname nvarchar(),
 shipphone nvarchar()
 )

CREATE TRIGGER tg_ship
ON  sales.shippers AFTER INSERT ,DELETE,UPDATE
as
INSERT INTO dbo.shiiper_log
        ( opdate ,
          opuser ,
          op ,
          shipname ,
          shipphone
        )
SELECT GETDATE() , -- opdate - datetime
          CURRENT_USER , -- opuser - nvarchar()
          N'插入' , -- op - nvarchar()
          companyname, -- shipname - nvarchar()
         phone  -- shipphone - nvarchar()
        FROM INSERTED;

SELECT * FROM dbo.shiiper_log;

INSERT INTO Sales.Shippers
        ( companyname, phone )
VALUES  ( N'Isoftstone', -- companyname - nvarchar()
          N''  -- phone - nvarchar()
          )

          --整个系统范围内
          SELECT @@IDENTITY;

          --当前作用域内最新的标识值
          SELECT SCOPE_IDENTITY();

          select  * FROM Sales.Shippers;