SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 `,i'vb`W#b
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一、基础 oJe9H <
1、说明:创建数据库 P1;T-.X~&
CREATE DATABASE database-name g9|B-1[
2、说明:删除数据库 L@2%a'
drop database dbname FL% GW:
3、说明:备份sql server 8:;_MBt
--- 创建 备份数据的 device ?jbE3fW
USE master *(YtO
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Yr@_X
--- 开始 备份 2ME"=!&5
BACKUP DATABASE pubs TO testBack 0JQy-hpF
4、说明:创建新表 6NH.!}"G9
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Eb SH)aR
根据已有的表创建新表: x^Tjs<#
A:create table tab_new like tab_old (使用旧表创建新表) @GqPU,RO
B:create table tab_new as select col1,col2... from tab_old definition only 1{4d)z UB
5、说明:删除新表 [Av#Z)R
drop table tabname @iK=1\-2
6、说明:增加一个列 0h-holUf}~
Alter table tabname add column col type _/ bF t6
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ^0"NcOzzxl
7、说明:添加主键: Alter table tabname add primary key(col) _
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说明:删除主键: Alter table tabname drop primary key(col) rGuhYYvK
8、说明:创建索引:create [unique] index idxname on tabname(col....) []:;8fY
删除索引:drop index idxname h^^zR)EVb
注:索引是不可更改的,想更改必须删除重新建。 4[a?..X
9、说明:创建视图:create view viewname as select statement yaD<jc(O
删除视图:drop view viewname hDJq:g
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10、说明:几个简单的基本的sql语句 {MdxIp[
选择:select * from table1 where 范围 `)e;bLP
插入:insert into table1(field1,field2) values(value1,value2) c[E{9wp v
删除:delete from table1 where 范围 Ou</{l/
更新:update table1 set field1=value1 where 范围 'Bb]<L`
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Epj
排序:select * from table1 order by field1,field2 [desc] J_YbeZ]
总数:select count as totalcount from table1 3{RuR+yi
求和:select sum(field1) as sumvalue from table1 J~KWn.
平均:select avg(field1) as avgvalue from table1 NLFs)6\
最大:select max(field1) as maxvalue from table1 GdG1e%y]z
最小:select min(field1) as minvalue from table1 PxzeN6f
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11、说明:几个高级查询运算词 7Ipt~K}
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A: UNION 运算符 B!GpD@U
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 H `y.jSNi
B: EXCEPT 运算符 v1<gNb)`
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 8^M5k%P
C: INTERSECT 运算符 $'e;ScH
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 I\DmVc\l
注:使用运算词的几个查询结果行必须是一致的。 eO;i1 >
12、说明:使用外连接 vF"<r,pg
A、left outer join: Z
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 DLcfOOn1I
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c JPfNf3<@My
B:right outer join: %<$CH],%
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 IK5FSN]s/
C:full outer join: L,!?'.*/]
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 d=V4,:=S
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二、提升 :0IxnK(r&
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _'<V<OjVM!
法一:select * into b from a where 1<>1 g0Qg]F5D~
法二:select top 0 * into b from a ;KJJK#j
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kRs[H xI3
insert into b(a, b, c) select d,e,f from b; [:sP Z{
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) %y.9S=,v,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 rt$zM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. pq_DYG]
4、说明:子查询(表名1:a 表名2:b) ~K% ]9
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) K:yS24\%
5、说明:显示文章、提交人和最后回复时间 mE)65@3%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {Uxah
6、说明:外连接查询(表名1:a 表名2:b) !3U1HS-i62
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Hn)K;?H4
7、说明:在线视图查询(表名1:a ) c:I1XC
select * from (SELECT a,b,c FROM a) T where t.a > 1; yveyAsN`B
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 H6E@C}cyM
select * from table1 where time between time1 and time2 ,Hh7'`
select a,b,c, from table1 where a not between 数值1 and 数值2 MuB8gSu
9、说明:in 的使用方法 3GqJs
select * from table1 where a [not] in ('值1','值2','值4','值6') XSt5s06TM
10、说明:两张关联表,删除主表中已经在副表中没有的信息 mNN,}nHu
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ZiM#g1;
11、说明:四表联查问题: $_ub.g|
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... '7o'u]
12、说明:日程安排提前五分钟提醒 @_^QBw0
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %Y%+K5;AZ
13、说明:一条sql 语句搞定数据库分页 :,rD5aOQ
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 4 q}1
14、说明:前10条记录 1<A+.W
select top 10 * form table1 where 范围 WI9'$hB\
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) )?~3fb6^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) y@]4xLB]
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 sN|-V+7&j
(select a from tableA ) except (select a from tableB) except (select a from tableC) zf$&+E-
17、说明:随机取出10条数据 Hb'fEo r
select top 10 * from tablename order by newid() Pc{D,/EpR
18、说明:随机选择记录 lMAmico
select newid() $UW!tg*U&
19、说明:删除重复记录 heoOOP(#
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) SFoF]U09
20、说明:列出数据库里所有的表名 $de_>
select name from sysobjects where type='U' (Tp+43v
21、说明:列出表里的所有的 8=gr F
select name from syscolumns where id=object_id('TableName') :Q2\3
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 8~RUYsg
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Dntcv|%u
显示结果: $D5[12X
type vender pcs 6CO>Tg:%
电脑 A 1 KIn^,d0H
电脑 A 1 y$s}-O]/-
光盘 B 2 L`FsK64@
光盘 A 2 )<G>]IP<
手机 B 3 AKx\U?ei7
手机 C 3 rMxst
23、说明:初始化表table1 {l{p
TRUNCATE TABLE table1 ?I}jsm1)
24、说明:选择从10到15的记录 s=#IoNh
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc qM3^)U2
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三、技巧 G+4a%?JH
1、1=1,1=2的使用,在SQL语句组合时用的较多 R4!qm0Cd
"where 1=1" 是表示选择全部 "where 1=2"全部不选, O/_}O_rR
如: Dn$zwksSs
if @strWhere !='' 1pXAPTV
begin OQ#gQ6;?0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere hDmtBdE
end $>'}6?C.
else J x-^WB
begin @A!Ef=R
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1w+OnJI?
end n-,~Bp
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我们可以直接写成 ]w%7/N0R
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere c}Jy'F7&f
2、收缩数据库 V)R-w`
--重建索引 N\H{p%8
DBCC REINDEX \ ^EjE
DBCC INDEXDEFRAG eC9~
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--收缩数据和日志 M7yJ2u <Ty
DBCC SHRINKDB M<7<L
DBCC SHRINKFILE v|_?qBs"
3、压缩数据库 l,h#RTfry
dbcc shrinkdatabase(dbname) 6`NsX
4、转移数据库给新用户以已存在用户权限 [#j|TBMHM
exec sp_change_users_login 'update_one','newname','oldname' OW)8Z60
go aO
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5、检查备份集 gb@Rx
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' |F<U;xV$p
6、修复数据库 }n=Tw92g
ALTER DATABASE [dvbbs] SET SINGLE_USER Ec_
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GO [HF)d#A
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZT8. r0
GO y>2v 9;Qp
ALTER DATABASE [dvbbs] SET MULTI_USER mfG|K@ODM-
GO pSQ3SM
7、日志清除 {eIE|
SET NOCOUNT ON tRbZ^5x\@
DECLARE @LogicalFileName sysname, U,iTURd
@MaxMinutes INT, #`z!f0
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@NewSize INT s`C#=l4
USE tablename -- 要操作的数据库名 dp)lHBV
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ++,mM7a
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ze WHSU
@NewSize = 1 -- 你想设定的日志文件的大小(M) TuIeaH% x
-- Setup / initialize kKE2~ q
DECLARE @OriginalSize int j])iyn~-Ke
SELECT @OriginalSize = size Iay7Fkv
FROM sysfiles ,-] JCcH
WHERE name = @LogicalFileName :KX/`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + d q:M!F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Btpx[T
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' q,u>`]}
FROM sysfiles Uj k``;
WHERE name = @LogicalFileName 5F^,7A4I0
CREATE TABLE DummyTrans 1b6gTfU
(DummyColumn char (8000) not null) xO1d^{~^^
DECLARE @Counter INT, 6J%SkuxR
@StartTime DATETIME, XF^c(*5
@TruncLog VARCHAR(255) \`>Y
SELECT @StartTime = GETDATE(), t T-]Vj.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6ap,XFRMh
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [FiXsYb.8
EXEC (@TruncLog) q6j]j~JxB
-- Wrap the log if necessary. /unOZVr(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Q2rZMK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) m
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AND (@OriginalSize * 8 /1024) > @NewSize )QBsyN<x6
BEGIN -- Outer loop. *tRJ=
SELECT @Counter = 0 apY m,_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) u8o7J(aQsR
BEGIN -- update 9\Xl3j!
INSERT DummyTrans VALUES ('Fill Log') 3M1(an\nW
DELETE DummyTrans e1<28g
SELECT @Counter = @Counter + 1 "a,Tc2xk
END Y%=A>~s*c:
EXEC (@TruncLog) WR'A%"qBwi
END 'c &Bmd40
SELECT 'Final Size of ' + db_name() + ' LOG is ' + +bRL.xY
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + WM@uxe,
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /E]4N=T
FROM sysfiles ew`R=<mZ,7
WHERE name = @LogicalFileName RtqW!ZZ:H
DROP TABLE DummyTrans B.Xm*adBT
SET NOCOUNT OFF }FM<uBKW
8、说明:更改某个表 Ccc6 ko_
exec sp_changeobjectowner 'tablename','dbo' ~Dy0HVE
9、存储更改全部表 w-\fCp )
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ;quGy3
@OldOwner as NVARCHAR(128), 3ZZJYf=
@NewOwner as NVARCHAR(128) IZ2#jSDn
AS U_VD* F4Bv
DECLARE @Name as NVARCHAR(128) k*M{?4
DECLARE @Owner as NVARCHAR(128) YRYrR|I
DECLARE @OwnerName as NVARCHAR(128) RhQOl9
DECLARE curObject CURSOR FOR Ix *KL=MG
select 'Name' = name, l^Lg"m2
'Owner' = user_name(uid) ]iz5VI@
from sysobjects G&uj}rj
where user_name(uid)=@OldOwner PTePSj1N
order by name 3ZB;-F5v
OPEN curObject 3_ zI$Z
FETCH NEXT FROM curObject INTO @Name, @Owner } KMdfA
WHILE(@@FETCH_STATUS=0) 6@I7UL >
BEGIN ^k)f oD
if @Owner=@OldOwner kW,yZ.?f
begin e.HN%LrhS
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <0kRky$
exec sp_changeobjectowner @OwnerName, @NewOwner (g4g-"rc
end (c}0Sg
-- select @name,@NewOwner,@OldOwner {M%"z,GL7J
FETCH NEXT FROM curObject INTO @Name, @Owner )>[(HxvfJU
END d>AVUf<o~
close curObject 8\a)}k~4
deallocate curObject a"&Z!A:Z=
GO sztnRX_
10、SQL SERVER中直接循环写入数据 huq6rA/i
declare @i int hCo&SRC/5
set @i=1 t]@Zd*
while @i<30 yNDyh
begin @+{S-iD"
insert into test (userid) values(@i) uY;/3?k&
set @i=@i+1 /kJ*WA?J
end M>]%Iu
小记存储过程中经常用到的本周,本月,本年函数 \JyWKET::_
Dateadd(wk,datediff(wk,0,getdate()),-1) 5#fLGXP
Dateadd(wk,datediff(wk,0,getdate()),6) =x^I 5Pn
Dateadd(mm,datediff(mm,0,getdate()),0) 6*LU+U=`
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) qq?>ulu*W
Dateadd(yy,datediff(yy,0,getdate()),0) tTmFJ5
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) C$%QVcf
上面的SQL代码只是一个时间段 l+N?:E$5=%
Dateadd(wk,datediff(wk,0,getdate()),-1) #|CG %w
Dateadd(wk,datediff(wk,0,getdate()),6) zm~~mz A
就是表示本周时间段. C>MoR 3]
下面的SQL的条件部分,就是查询时间段在本周范围内的: 22*t%{(
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) k|lxJ^V#
而在存储过程中 BF_k~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \E#r[9F{
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &U,f~KJ