http://www.cnblogs.com/zxlovenet/p/3728842.html

本文語句大部分SQL語句來自《數據庫系統概論》（第四版）王珊&薩師煊 ，是我們上課用的教材，感覺很不錯，總結了其中第三章的SQL語句，比較實用，希望對大家有幫助。總結如下，可以用來學習基礎的SQL語句。

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建立數據庫

CREATE DATABASE DB_Student

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建立表

CREATE TABLE Student

??? (Sno CHAR(9) PRIMARY KEY,--主碼

??? Sname CHAR(20) UNIQUE,--唯一值

??? Ssex CHAR(2),

??? Sage SMALLINT,

??? Sdept CHAR(20)

??? );

CREATE TABLE Course

??? (Cno CHAR(4) PRIMARY KEY,

??? Cname char(40),

??? Cpno CHAR(4),

??? Ccredit SMALLINT,

??? FOREIGN KEY (Cpno) REFERENCES Course(Cno)

??? );

CREATE TABLE SC

??? (Sno CHAR(9),

??? ?Cno CHAR(4),

??? ?Grade SMALLINT,

??? ?PRIMARY KEY (Sno,Cno),

??? ?FOREIGN KEY (Sno) REFERENCES Student(Sno),--外碼

??? ?FOREIGN KEY (Cno) REFERENCES Course(Cno)

??? );

數據

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表操作

alter table Student add S_entrance date--增加列

alter table student alter column Sage int--修改字段類型

alter table course add unique (Cname)--增加唯一性約束

drop table Student--刪除基本表

drop table student cascade--刪除基本表及相關依賴對象

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創建索引

drop index stusname

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查詢數據

select sno,sname from student

select sname,sno,sdept from student

select sname,2004-sage from student

select sname,'Year of Birth:',2004-sage, lower(sdept) from student--查詢結果第二列是一個算數表達式

select sname name,'Year of Birth:' BIRTH,2004-sage birthday,LOWER(sdept) department from student--LOWER()小寫字母

select sno from sc

select distinct sno from sc--消除重復行

select sno from sc

select all sno from sc

select sname from student where sqept='CS'

--=、>、<、>=、<=、!=、<>、!>、!<? 比較的運算符

select sname,sage from student where sage<20

select distinct sno from sc where sage<20

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select sname,sdept,sage from student where sage between 20 and 23

select sname,sdept,sage from student where sage not between 20 and 23

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select sname,ssex from student where sdept in ('CS','MA','IS')

select sname,sage from student where sdept not in('CS','MA','IS')

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select * from student where sno like '200215121'

select * from student where sno='200215121'

--字符匹配

--% 任意長度字符串，_ 任意單個字符，ESCAPE 轉義字符

select sname,sno,ssex from student where sname like '劉%'

select sname from student where sname like '歐陽__'

select sname,sno from student where sname like '__陽%'

select sname,sno,ssex from student where sname not like '劉%'

select cno,ccredit from course where cname like 'DB\_design' escape '\'

select * from course where cname like 'DB\_%i__' escape '\'

select sno,cno from sc where grade is null --null 空值

select sno,cno from sc where grade is not null

select sname from student where sdept='CS' and sage<20

select sname,sage from studnet where sdept='CS' or sdept='MA' or sdept='IS'

select sno,grade from sc where cno='3' order by grade desc -- order by 排序

select * from student order by sdept,sage desc --空值最大

--聚集函數

select count(*) from student -- count() 行數

select count(distinct sno) from sc

select avg(grade) from sc where cno='1' -- avg() 平均數

select max(grade) from sc where cno='1' -- max() 最大值

select sum(Ccredit) from sc,course where sno='200215012' and sc.cno=course.cno -- sum() 總數

--分組

select cno,count(sno) from sc group by cno

select sno from sc group by sno having count(*) >3 --having 給出選擇組的條件

--連接查詢

select student. *,SC.* FROM STUDENT,SC where student.sno=sc.sno

select student.sno,sname,ssex,sage,sdept,cno,grade from student,sc where student.sno =sc.sno

select first.cno,second.cpno from course first,course second fwhere first.cpno=second.cno -- 自身連接

select student.sno,sname,ssex,sage,sdept,cno,grade from student left out join sc in (student.sno=sc.sno)--外連接

--from student left out join sc using (sno)

select student.sno,sname from student,sc where student.sno=sc.sno and sc.cno='2' and sc.grade>90

select student.sno,sname,cname,grade from student,sc,course where student.sno=sc.sno and sc.cno=course.cno

select sname from student where sno in (select sno from sc shere con='2')

select sdept from student where sname='劉晨'

select sno.sname,sdept from student where sdept='CS'

--嵌套查詢

select sno,sname,sdept from student where sdept in (select sdept from studnet where sname='劉晨')

select sno,sname,sdept from student where sdept in ('CS')

select s1.sno,s1.sname,s1.sdept from student s1,student s2 where s1.sdept =s2.sdept and s2.sname='劉晨'

select sno,sname from student where sno in (select sno from sc where cno in(select cno from course where cname='信息系統'))

select student.sno,sname from student ,sc,course where student.sno=sc.sno and sc.cno =course.cno and course.cname='信息系統'

--內查詢的結果是一個值，因此可以用=代替in

select sno,sname,sdept from student where sdpet=(se3lect sdept from studnet where sname='劉晨')

select sno,sname,sdept from student where(select sdept from student where sname='劉晨')=sdept

select sno,cno from sc x where grade >=(select avg(grade) from sc y where y.sno=x.sno)

select avg(grade) from sc y where y.sno='200215121'

select sno,cno from sc x where grade>=88

select sname,sage from student where sage <ANY (SELECT sage from student where sdept='CS') and sdept <>'CS'

select sname,sage from student where sage<(select max(sage) from student where sdept='CS') and sdept <> 'CS'

select sname,sage from student where sage < all (select sage from student where sdept ='CS')

select sname,sage from student where sage<(select min(sage) from student where sdept='CS') and sdept <>'CS'

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select sname from student where exists(select * from sc where sno=student.sno and cno='1')

select sname from student where not exists (select * from sc where sno=student.sno and cno='1')

select sno.sname,sdept from student s1 where exists(select * from studetn s2 where s2.sdept=s1.sdept and s2.sname='劉晨')

select sname from student where not exists (select * from course where not exists(select * from sc where sno=student.sno and cno=course.cno))

select distinct sno frome sc scx where not exists (select * from sc scy where scy.sno='200215122' and not exists(select * from sc scz where scz.sno=scx.sno and scz.cno=scy.cno))

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集合查詢

select * from student where sdept ='CS' union select * from student where sage<=19 --union并操作

select sno from sc where cno='1' union select sno from sc where sc where cno='2'

select * from student where sdept='cs' intersect select * from student where sage<=19 --intersect 交操作

select * from student where sdept='cs' and sage<=19

select sno from sc where cno='1' intersect select sno from sc where cno='2'

select sno from sc where cno='1' and sno in (select so from sc where cno='2')

select * from student where sdept='cs' except select * from student where sage<='19' --except 差操作

select * from student where sdept ='cs' and sage>19

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插入數據

insert into student(sno,sname,ssex,sdept,sage) values('200215128','陳東','男','IS','18')

insert into student values('200215126','張成敏','男','18','cs')

insert into sc(sno,cno) values('200215128','1')

insert into sc values('200215128','1',null)

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更新數據

create table dept_age(sdept char(15) avg_agea smallint)

insert into dept_age(sdept,avg_age) select sdept,avg(sage) from student group by sdept

update student set sage=22 where sno='200215121'

update student set sage=sage+1

update sc set grade=0 where 'cs'=(select sdept from student where student.sno=sc.sno)

update is_student set sname='劉晨' where sno='200215122'

update student set sname='劉晨' where sno='200212122' and sdept='IS'

delete from student where sno='200215128'

delete from is_student where sno='200215129'

delete from student where sno='200215129' and sdept='IS'

delete from sc

delete fro sc where 'cs'=(select sdept from student where student.sno=sc.sno)

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刪除操作

delete from Student where Sno=’200215128’

delete from SC

delete from SC where ‘cs’ = (select Sdept from Student where Student.Sno=SC.Sno)

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創建視圖

create view is_student

as

select sno,sname,sage from student where sdpet='IS'

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create view is_student

as

select sno,sname,sage from student where sdept='IS' with check option

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create view is_s1(sno,sname,grade)

as

select student.sno,sname,grade from student,sc where student,sc where sdept=='IS' and student.sno=sc.sno and sc.cno='1'

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create view is_s2

as

select sno,sname,grade from is_s1 where grade>=90

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create view bt_s(sno,sname,sbirth)

as

select sno,sname,2004-sage from student

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create view s_g(sno,gavg)

as

select sno,avg(grade) from sc group by sno

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create view f_student(f_sno,name,sex,age,dept)

as

select * from student where ssex='女'

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刪除視圖

drop view is_s1 cascade

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select sno,sage from is_student where sage<20

select sno,sage from student where sdept='IS' and sage<20

select is_sutdent.sno,sname from is_student,sc where is_student.sno=sc.sno and sc.cno='1'

select * from s_g where gavg>=90

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分組

select sno,avg(grade) from sc group by sno

select sno,avg(grade) from sc where avg(grade)>=90 group by sno

select sno,avg(grade) from sc group by sno having avg(grade) >=90

存儲過程

CREATE PROCEDURE Insert_pass

@pass NVARCHAR(50)

AS

? BEGIN

????? DECLARE @count INT

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????? SELECT @count = (SELECT Count(*)

?????????????????????? FROM?? list

?????????????????????? WHERE? pass = @pass)

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????? IF @count = 0

??????? BEGIN

??????????? INSERT INTO list

??????????????????????? (pass)

??????????? VALUES???? (@pass)

??????? END

? END

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執行存儲過程

call procedure Insert_pass(2011)

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刪除存儲過程

drop procedure Insert_pass()

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觸發器

CREATE TRIGGER insert_table1

ON table1

FOR INSERT, DELETE

AS

? BEGIN

????? UPDATE table2

????? SET??? count = (SELECT Count(*)

????????????????????? FROM?? table1)

????? WHERE? id = 1;

? END;

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游標：游標是系統為用戶開設的一個數據緩沖區，存放SQL語句的執行結果，每個游標區都有一個名字。用戶可以通過游標逐一獲取記錄，并賦值給主變量，交由主語言進一步處理。

轉載于:https://www.cnblogs.com/whl4835349/p/6047644.html

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