--**建立資料庫

create database test on primary (     name='testsql',     filename='E:\test1.mdf',     size=5mb,     maxsize=100mb,     filegrowth=15% ) log on  (     name='testlog',     filename='E:\testlog.ldf',     size=5mb,     maxsize=50mb,     filegrowth=1mb ) use test

--**建立table create table classinfo (     cid int not null primary key identity(1,1),     ctitle nvarchar(5) ) create table scoreinfo (     scid int not null primary key identity(1,1),     score varchar(4) )

create table studentinfo (     sid int not null primary key identity(1,1),     sname nvarchar(10),     sgender bit default(0),     sphone char(11),     saddress nvarchar(20),     semail varchar(15),     Cid int not null,     foreign key (Cid) references classinfo(cid),     foreign key (Cid) references scoreinfo(scid) )--***插入資訊***

select * from classinfo  insert into classinfo (ctitle) values ('1班'),('2班'),('3班'),('4班'),('5班') select * from scoreinfo insert into scoreinfo (score) values ('99'),('34'),('21'),('45'),('50'),('55'),('60'),('70'),('80'),('90'),('100')

select * from studentinfo  insert into studentinfo values ('張三',0,'15656282598','TLU','

[email protected]',1), ('李四',0,'15656288499','CZU','[email protected]',2), ('王五',0,'15656288597','SHU','[email protected]',3), ('劉七',1,'15656288596','BJU','[email protected]',4), ('趙八',0,'13030118598','JPU','[email protected]',1), ('錢二',0,'13022112198','WZU','[email protected]',2), ('吳一',1,'15623028590','CYU','[email protected]',3)

--***更新資訊*** update studentinfo set sname='周九',sphone='13113016396',saddress='SGU',semail='[email protected]' where sid=3

--***刪除資訊*** delete from studentinfo where sid=11

--***查詢資訊*** select sname  from studentinfo

--*起別名* select sname as '姓名' ,  sgender as Gender from studentinfo

--one 查詢前N部分 select top 5 sname from studentinfo--one 查詢前N部分 select top 5 sname , sgender from studentinfo--one 查詢前N部分 select top 5 sname as '姓名' , sgender as Gender from studentinfo

--two 查詢前N部分 select top 20 percent * from studentinfo--two 查詢前N部分 select top 20 percent sname as '姓名' from studentinfo--two 查詢前N部分 select top 30 percent * from studentinfo where sid=3--*排序* select top 90 percent * from studentinfo order by sid ASC

select top 90 percent * from studentinfo order by sid DESC , semail ASC

--*消除重複行* select distinct * from studentinfo

--***條件查詢 寫在where後*** --*比較運算子* select * from studentinfo where sid>5

select * from studentinfo where sid> 5 and sid< 10

select top 20 percent sname as '姓名' ,sid from studentinfo where sid != 2

--*連續型between ..and..* select * from studentinfo where sid between 3 and 8 and sid !=4

--*間斷型in* select * from studentinfo where sid in(3,8)

--*邏輯運算子and not or* select * from studentinfo where sid>2 and sid<10

select * from studentinfo where not sid between 3 and 8 

select * from studentinfo where sid between 3 and 8 or sgender=0

--*模糊查詢針對字串 like % _ ^ []* select *  from studentinfo where sname like '_[^三]' and sname like '_[四]'

select * from studentinfo where sphone like '___130%'

select *  from studentinfo where semail like '%@qq%'

--***兩表資料連線查詢***並不需要有主外來鍵，有相同的欄位即可 select * from studentinfo inner join  classinfo on  studentinfo.cid=classinfo.cid inner join scoreinfo on studentinfo.cid=scoreinfo.scid

select * from studentinfo as si full join  classinfo on si.cid= classinfo.cid

select si.sname,si.sphone,ci.ctitle,sci.score from studentinfo as si full join classinfo as ci on si.Cid=ci.cid left join scoreinfo as sci on si.Cid=sci.scid

--***聚合函式sum，avg，count，max，min select count(*) as count_numb from studentinfo

select count(*) from studentinfo where sphone is null

select max(score) from scoreinfo

--AVG必須是int型別 select AVG(score) from scoreinfo full join studentinfo as si on scoreinfo.scid=si.Cid

select MIN(score) from scoreinfo full join studentinfo as si on scoreinfo.scid=si.Cid

select MAX(score) from scoreinfo full join studentinfo as si on scoreinfo.scid=si.Cid where sgender=0

--***聚合函式***over()通常和聚合函式,排名函式使用 --sci.score是N行，而avg(score)是一行，合併要用over()函式 select sci.score ,AVG(score) over(  order by  score ) as '平均值' from studentinfo as si inner join scoreinfo as sci on si.Cid=sci.scid  

--***分組函式***group by() select sgender,count(*) from studentinfo group by sgender

use test select * from studentinfo

select sname,COUNT(*) from studentinfo group by sname

select sname,sphone,COUNT(*) from studentinfo group by sname,sphone

--*分組過後又想再進行分組having,就是從分好的資料中再摘取想要的資料* --*但是having的條件應該是原select裡的 --group by 後面的決定select後面的 select sname,sphone,count(*) from studentinfo where sid>4 group by sname,sphone  having count(*)>1

select sname,sphone,count(*) from studentinfo where sid>4 group by sname,sphone having sphone like '130%'

/**查詢總結

select distinct top 6 |percent *  from studentinfo inner join -- on -- left join -- on --  right join -- on -- where -- group by  order by  **/--**聯合查詢,將兩個資料表(or 各表的查詢結果連線在新的資料集中， --**但要保證各集中查詢結果的列數和型別要保持相同) --union、union all、except、intersect select sid from studentinfo union            --去掉兩個資料集中重複的欄位 select cid from classinfo

select sid from studentinfo union all            --bu 去掉兩個資料集中重複的欄位 select cid from classinfo

select sid from studentinfo except            --1與2交集的補集（1） select cid from classinfo

select sid from studentinfo intersect            --交集 select cid from classinfo

--**快速備份**新表不會包含原表的約束(主鍵、外來鍵) --select 列名 into 備份表 from 原表 select *  into test1 from studentinfo--只要表的結構不要資料(加一個不true的where語句) select * into test2 from classinfo where 1=2--**快速備份**向已存在的表插入資料 --insert into 已存在備份表（列） select 列 from 原表 insert into test2(ctitle)   select sname from studentinfo--**型別轉換 cast  convert select cast(89.0000 as decimal(4,1)) select  convert(decimal(4,1),89.000)

--**建立檢視** 檢視只用來儲存sql語句 select * from studentinfo inner join classinfo on studentinfo.Cid=classinfo.cid where studentinfo.sname like '_[^三]'

create view student_class as select studentinfo.*,classinfo.ctitle from studentinfo inner join classinfo on studentinfo.Cid=classinfo.cid  

select sname from student_class

where studentinfo.sname like '_[^三]'

--修改alter alter view student_class as select studentinfo.*,classinfo.ctitle from studentinfo inner join classinfo on studentinfo.Cid=classinfo.cid

--刪除drop drop view student_class

--**子查詢** in /exists 後者效率高 use test select * from studentinfo where Cid in (select cid from  classinfo)

select * from studentinfo where exists (select * from classinfo where studentinfo.Cid=classinfo.cid)

--*分頁查詢   將sid重編碼為index（因為sid可能會丟失跳段，如刪除） select * from  (select *,ROW_NUMBER() over(order by sid desc) as rowindex  from studentinfo) as t1 where rowindex between 2 and 7