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。
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一、基础 dW%t ph
1、说明:创建数据库 fLqjBG]<
CREATE DATABASE database-name T.3{}230<
2、说明:删除数据库 tsL
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drop database dbname l
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3、说明:备份sql server 1O<6=oH
--- 创建 备份数据的 device g4b#U\D@)/
USE master IdN3Ea]
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' / Ws>;0
--- 开始 备份 Sc/l.]k+
BACKUP DATABASE pubs TO testBack l cHf\~
4、说明:创建新表 a#"orc j
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sYBmL]Hr
根据已有的表创建新表: Zp3-Yo w2
A:create table tab_new like tab_old (使用旧表创建新表) >h)kbsSU0z
B:create table tab_new as select col1,col2... from tab_old definition only bXvO+I<
5、说明:删除新表 `-.2Z
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drop table tabname pB\:.?.pd
6、说明:增加一个列 r
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Alter table tabname add column col type 8-NycG&)
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。 cz1 + XpU
7、说明:添加主键: Alter table tabname add primary key(col) ij;NM:|Sd
说明:删除主键: Alter table tabname drop primary key(col) \fUX_0k9,
8、说明:创建索引:create [unique] index idxname on tabname(col....) z4Zm%
删除索引:drop index idxname JPAjOcmU/
注:索引是不可更改的,想更改必须删除重新建。 g i6s+2
9、说明:创建视图:create view viewname as select statement L7;~4_M9.V
删除视图:drop view viewname oe] *Q
10、说明:几个简单的基本的sql语句 :`zO%h
选择:select * from table1 where 范围 P%lD9<jED
插入:insert into table1(field1,field2) values(value1,value2) s{R,- \_
删除:delete from table1 where 范围 _%=CW'
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更新:update table1 set field1=value1 where 范围 3 a.!9R>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \?
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排序:select * from table1 order by field1,field2 [desc] erW2>^My
总数:select count as totalcount from table1 V~[b`&F
求和:select sum(field1) as sumvalue from table1 Gmi?xGn
平均:select avg(field1) as avgvalue from table1 J)Y`G4l2@
最大:select max(field1) as maxvalue from table1 e)n ,Y
最小:select min(field1) as minvalue from table1 y;Cs#eo
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11、说明:几个高级查询运算词 '"E!av>
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A: UNION 运算符 p$9Aadi]
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。 / Qd` ?
B: EXCEPT 运算符 U,#x\[3!Jt
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。 lQ`=PFh
C: INTERSECT 运算符 :>{!%-1Z
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。 H^*AaA9-
注:使用运算词的几个查询结果行必须是一致的。 A6]X
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12、说明:使用外连接 M,_
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A、left outer join: &{.IUg
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。 Z8ea)_{#
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 G|f9l?p
B:right outer join: cVW7I
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。 BYX c
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C:full outer join: :vb5J33U
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。 wDh]vH[
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二、提升 HvG %##
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 ZI!:
法二:select top 0 * into b from a }6%XiP|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) r[i^tIv6As
insert into b(a, b, c) select d,e,f from b; qIQ=OY=6
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) B223W_0"o
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (l^7EpNs
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {\D&*
4、说明:子查询(表名1:a 表名2:b) KJ'ID
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) qx5`lm~L
5、说明:显示文章、提交人和最后回复时间 i`2SebDj'w
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b c%/b*nQ(=
6、说明:外连接查询(表名1:a 表名2:b) \L(cFjLIl
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |qn2b=
7、说明:在线视图查询(表名1:a ) W :]2Tp
select * from (SELECT a,b,c FROM a) T where t.a > 1; e9{0hw7
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 dgpE3
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select * from table1 where time between time1 and time2 !2KQi=Ng
select a,b,c, from table1 where a not between 数值1 and 数值2 PiKP.
9、说明:in 的使用方法 o@zxzZWg
select * from table1 where a [not] in ('值1','值2','值4','值6') :TU|:2+
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ZQE1]ht
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) sh_;98^
11、说明:四表联查问题: z;>$["t]6
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... C*b[J
12、说明:日程安排提前五分钟提醒 9Vm1q!lE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ][S q^5`
13、说明:一条sql 语句搞定数据库分页 6XWNJb
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 4-.K<-T%D
14、说明:前10条记录 b!@PS$BTxq
select top 10 * form table1 where 范围 ^7spXfSAd
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.) /%& d:
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ]@Zv94Z(
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 6i[Ts0H%<!
(select a from tableA ) except (select a from tableB) except (select a from tableC) >N Bc-DX^
17、说明:随机取出10条数据 'NlhLu
select top 10 * from tablename order by newid() [
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18、说明:随机选择记录 P 0.cF]<m
select newid() eZPeyYX
19、说明:删除重复记录 )*]A$\Oc[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) R7Y_ 7@p
20、说明:列出数据库里所有的表名 x8rg/y
select name from sysobjects where type='U' pr#%VM[':R
21、说明:列出表里的所有的 WT ;2aS:
select name from syscolumns where id=object_id('TableName') SUUNC06V
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。 o4kLgY !Q
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 &" t~d}Rg
显示结果: w.k9{f
type vender pcs t<##0#xS.
电脑 A 1 [_'A(.
电脑 A 1 y{hg4|\
光盘 B 2 }:IIk-JoC
光盘 A 2 fwz:k]vk
手机 B 3 G{} 2"/
手机 C 3 2L](4Q[M
23、说明:初始化表table1 GM%OO)dO}
TRUNCATE TABLE table1 y8~OkdlN#
24、说明:选择从10到15的记录 SCcvU4`o
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \ZLi Y
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三、技巧 $os]$5(
1、1=1,1=2的使用,在SQL语句组合时用的较多 #-'`Ybw
"where 1=1" 是表示选择全部 "where 1=2"全部不选, V6][*.i!9
如: OS,!`8cw
if @strWhere !='' *<xu3){:c
begin uslu-|b!%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere "@nH;Xlq
end 4?+K
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else l/G+Xj4M
begin dxs5woP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,' |J
end s-"KABEE
我们可以直接写成 _Z0 .c@0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere N5 5F5
2、收缩数据库 :VT%d{Vp_
--重建索引 uB
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DBCC REINDEX g{]6*`/Z
DBCC INDEXDEFRAG #%;Uh
--收缩数据和日志 .]vb\NBK7
DBCC SHRINKDB |eu8;~A
DBCC SHRINKFILE ytIPY7E
3、压缩数据库 oVpZR$
dbcc shrinkdatabase(dbname) WoZU} T-
4、转移数据库给新用户以已存在用户权限 ;W?#l$R
exec sp_change_users_login 'update_one','newname','oldname' j?N<40z
go Mr)t>4
5、检查备份集 h =A
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' jKml:)k
6、修复数据库 0zH-g
ALTER DATABASE [dvbbs] SET SINGLE_USER =1Sny7G
GO 0/)2RmF
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -iR2UE@M
GO dC({B3#e{
ALTER DATABASE [dvbbs] SET MULTI_USER qf x*a88
GO sGu.G
7、日志清除 PGP#$JC
SET NOCOUNT ON O6G\0o
DECLARE @LogicalFileName sysname, KHAc!4lA
@MaxMinutes INT, ~!Nj DDk
@NewSize INT fmuh9Z
USE tablename -- 要操作的数据库名 "A}sD7xy9
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 6'^E
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;TJpD0
@NewSize = 1 -- 你想设定的日志文件的大小(M) n*7^lAa2
-- Setup / initialize +c~&o83[
DECLARE @OriginalSize int zTa5N
SELECT @OriginalSize = size x:FZEyalG
FROM sysfiles 9w=7A>.U
WHERE name = @LogicalFileName +7gd1^|$e
SELECT 'Original Size of ' + db_name() + ' LOG is ' + x &R9m,
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + QR&e~rks
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' _^BA;S@
FROM sysfiles cHvm
WHERE name = @LogicalFileName JUr
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CREATE TABLE DummyTrans \78E>(`'
(DummyColumn char (8000) not null) qYA~Os1e
DECLARE @Counter INT, Yg8*)u0
@StartTime DATETIME, -P;0<j@6k5
@TruncLog VARCHAR(255) , MXU]{
SELECT @StartTime = GETDATE(), T<B}Z11R
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4QA~@pBX^{
DBCC SHRINKFILE (@LogicalFileName, @NewSize) !_W/p`Tc
EXEC (@TruncLog) s/7Z.\
-- Wrap the log if necessary. *tUOTA 3L
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 3>h2W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^bv^&V&IB
AND (@OriginalSize * 8 /1024) > @NewSize q-`&C
BEGIN -- Outer loop. SZKYq8ZA)V
SELECT @Counter = 0 ~,}|~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M(a%Qk?]/
BEGIN -- update Vc9rc}
INSERT DummyTrans VALUES ('Fill Log') %V>%AP
DELETE DummyTrans e-rlk5k%f
SELECT @Counter = @Counter + 1 MZV$YD^S
END x4*
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EXEC (@TruncLog) INA3^p'w
END F^.A~{&L
SELECT 'Final Size of ' + db_name() + ' LOG is ' + fbh,V%t7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + NT+.E[J6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' =^KgNQ
FROM sysfiles Nm"P8/-09
WHERE name = @LogicalFileName 1sHjM%
DROP TABLE DummyTrans mXz*Gi
SET NOCOUNT OFF $9`#p/V
8、说明:更改某个表 uHKEt[PS$
exec sp_changeobjectowner 'tablename','dbo' *a Z1 4
9、存储更改全部表 76 !LMNf
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch :i<*~0r<
@OldOwner as NVARCHAR(128), zP,r,ok7
@NewOwner as NVARCHAR(128) 4k225~GQ:C
AS D./{f8
DECLARE @Name as NVARCHAR(128) E]'
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DECLARE @Owner as NVARCHAR(128) (u &x.J
DECLARE @OwnerName as NVARCHAR(128) Or? )Nlg6x
DECLARE curObject CURSOR FOR 7FE36Ub9
select 'Name' = name, ;dzL9P9IU
'Owner' = user_name(uid) KUJ Lx
from sysobjects TaRPMKk
where user_name(uid)=@OldOwner VW\S>=O99
order by name w1tM !4r
OPEN curObject /wLBmh1"
FETCH NEXT FROM curObject INTO @Name, @Owner q SNCBn '
WHILE(@@FETCH_STATUS=0) rQ.zqr
BEGIN o-=|}u]mz
if @Owner=@OldOwner f8;?WSGyD2
begin }<^mUG
set @OwnerName = @OldOwner + '.' + rtrim(@Name) OInl?_,,T#
exec sp_changeobjectowner @OwnerName, @NewOwner (p5q MP]L
end t$$YiO
-- select @name,@NewOwner,@OldOwner bny5e:= d
FETCH NEXT FROM curObject INTO @Name, @Owner *\XOQWrF
END I;w!
close curObject B$g\;$G
deallocate curObject 'W(u.
GO xq((]5P y
10、SQL SERVER中直接循环写入数据 GURiW42
declare @i int ~]-n%J$q
set @i=1 U
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while @i<30 RB %+|@c
begin t1w]L
insert into test (userid) values(@i) +;~N; BT
set @i=@i+1 "s0,9;
}
end (vG*)a
小记存储过程中经常用到的本周,本月,本年函数 Dz0D ^(;V
Dateadd(wk,datediff(wk,0,getdate()),-1) o ks;G([
Dateadd(wk,datediff(wk,0,getdate()),6) @%,~5{Ir
Dateadd(mm,datediff(mm,0,getdate()),0) 7su2A>Ix
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) qTJ0}F
Dateadd(yy,datediff(yy,0,getdate()),0) gkd4)\9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `^[k8Z(
上面的SQL代码只是一个时间段 A;L
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Dateadd(wk,datediff(wk,0,getdate()),-1) N~,Ipf
Dateadd(wk,datediff(wk,0,getdate()),6) O]tR~a
就是表示本周时间段. )jOa!E"
下面的SQL的条件部分,就是查询时间段在本周范围内的: ui>jJ(
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Kzrd<h]`)
而在存储过程中 uP* kvi:e
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) RxqNgun@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)
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