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。 {&6i$4T
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一、基础 h 'Hnq m
1、说明:创建数据库 % w
CREATE DATABASE database-name Fw}|c
2、说明:删除数据库 }O| 9Qb
drop database dbname S a}P
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3、说明:备份sql server cz|?j
--- 创建 备份数据的 device @*|T(068&
USE master UG}2q:ST
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P^<to(|
--- 开始 备份 D`KaIqLz
BACKUP DATABASE pubs TO testBack =4V SbOlZ
4、说明:创建新表 *D9H3M[o#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _,d<9 Y)
根据已有的表创建新表: &rl;+QS
A:create table tab_new like tab_old (使用旧表创建新表) roBb8M|q
B:create table tab_new as select col1,col2... from tab_old definition only ~_g{P3
5、说明:删除新表 @S>;t)\J
drop table tabname Ap4.c8f?Q-
6、说明:增加一个列 | :id/
Alter table tabname add column col type )%lPKp4]
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。 {2i8]Sp1d/
7、说明:添加主键: Alter table tabname add primary key(col) 33&\E- Q>
说明:删除主键: Alter table tabname drop primary key(col) _c5*9')-)
8、说明:创建索引:create [unique] index idxname on tabname(col....) 4:/^ .:
删除索引:drop index idxname - leYR`P
注:索引是不可更改的,想更改必须删除重新建。 |f.,fVVV;
9、说明:创建视图:create view viewname as select statement Q7tvpU
删除视图:drop view viewname 6GqC]rd*:
10、说明:几个简单的基本的sql语句 $ \o)-3
选择:select * from table1 where 范围 F!*GrQms
插入:insert into table1(field1,field2) values(value1,value2) w8 `1'*HG
删除:delete from table1 where 范围 k_Y7<z0G
更新:update table1 set field1=value1 where 范围 es=OWJt^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! !_B*Po
排序:select * from table1 order by field1,field2 [desc] -*Th=B-
总数:select count as totalcount from table1 9QL%q;
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求和:select sum(field1) as sumvalue from table1 _-9cGm v
平均:select avg(field1) as avgvalue from table1 DQaE9gmC
最大:select max(field1) as maxvalue from table1 =);@<Jp
最小:select min(field1) as minvalue from table1 j['B9vG
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11、说明:几个高级查询运算词 Xil;`8h
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A: UNION 运算符 HPJHA ,
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。 1MT,A_L
B: EXCEPT 运算符 f*9O39&|
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。 7q5*grm
C: INTERSECT 运算符 =2ED
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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。 g2=PZR$
注:使用运算词的几个查询结果行必须是一致的。 ts=:r
12、说明:使用外连接 49c-`[d
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A、left outer join: ~!cxRd5;F
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。 %qTIT?6'
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 6<R[hIWpZ}
B:right outer join: ZmNNR 1%/
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。 p(8 @
C:full outer join: *c&|2EsZ
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。 jIVD i~Ld
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二、提升 ?( z"Ub]
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) VxARJ*4=Y
法一:select * into b from a where 1<>1 a6 0rJ#GD
法二:select top 0 * into b from a F[`dX
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) cUdS{K&K
insert into b(a, b, c) select d,e,f from b; V*@Y9G
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) 4RYH^9;>K
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 @qj]`}Gx'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. |r36iUHZS
4、说明:子查询(表名1:a 表名2:b) CyW|k
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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) >xq.bG
5、说明:显示文章、提交人和最后回复时间 m8e()8lZ3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Kfr1k
6、说明:外连接查询(表名1:a 表名2:b) kxJ[Bi#
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c j0V/\Ep)T<
7、说明:在线视图查询(表名1:a ) s(J>yd=
select * from (SELECT a,b,c FROM a) T where t.a > 1; FF!PmfF'
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 ela^L_N hF
select * from table1 where time between time1 and time2 mtn^+*
select a,b,c, from table1 where a not between 数值1 and 数值2 U V*Ruy-
9、说明:in 的使用方法 7]ysvSM
select * from table1 where a [not] in ('值1','值2','值4','值6') SgehOu
10、说明:两张关联表,删除主表中已经在副表中没有的信息 )|^8`f
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0K26\1
11、说明:四表联查问题: H:~u(N
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 ..... rD a{Ve
12、说明:日程安排提前五分钟提醒 &>E gKL
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 '%XYJr:H[
13、说明:一条sql 语句搞定数据库分页 \IImxkE
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 oOU_
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14、说明:前10条记录 Hq 3V+$
select top 10 * form table1 where 范围 OE9,D:tv
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.) }2Euz.0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) \=bKuP(it
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 2A[hMbL
(select a from tableA ) except (select a from tableB) except (select a from tableC) #Lp}j?Y
17、说明:随机取出10条数据 0<NS1y
select top 10 * from tablename order by newid() v$Hz)J.01
18、说明:随机选择记录 zyUS$g]&
select newid() MGt>:&s(]
19、说明:删除重复记录 #
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) $T^q>v2u
20、说明:列出数据库里所有的表名 &ah%^Z4um
select name from sysobjects where type='U' ]a4+] vLK
21、说明:列出表里的所有的 yNP4Ey
select name from syscolumns where id=object_id('TableName') V-n{=8s
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。 vZ"gCf3#?3
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 m m`#v
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显示结果: \AKP ea=
type vender pcs ||awNSt
电脑 A 1 bvB',yBZ
电脑 A 1 =\5WYC
光盘 B 2 hpb|| V
光盘 A 2 z+{qQ!
手机 B 3 }&e HU
手机 C 3 C49\'1\6
23、说明:初始化表table1 X.k8w\~
TRUNCATE TABLE table1 ce}A!v
24、说明:选择从10到15的记录 }6/M5zF3
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ~uty<fP
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三、技巧 )&d=2M;3
1、1=1,1=2的使用,在SQL语句组合时用的较多 H>%AK''
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $["HC-n?.k
如: j9hfW'
if @strWhere !='' =2Yt[8';
begin ['.])
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #]tDxZ]
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end Hy&Z0W'l
else #?>)5C\Hqy
begin ]Z8u0YtM)
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?{J1Uw<
end 3zD#V3=
我们可以直接写成 GyN|beou
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C|TQf8
2、收缩数据库 >Wt@O\k
--重建索引 e8^/S^ =&d
DBCC REINDEX m1Y a
DBCC INDEXDEFRAG tjb$MW$('
--收缩数据和日志 TZt;-t`
DBCC SHRINKDB T :d+Qz\
DBCC SHRINKFILE xw
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3、压缩数据库 R P<M
dbcc shrinkdatabase(dbname) phjM(lmCo
4、转移数据库给新用户以已存在用户权限 RBn/7
exec sp_change_users_login 'update_one','newname','oldname'
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go L,y
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5、检查备份集 (4/"uj5
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $Z#~wsw
6、修复数据库 *u"%hXR
ALTER DATABASE [dvbbs] SET SINGLE_USER 8:V,>PH
GO nsU7cLf"^V
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK m[v0mXE
GO F{E@snc
ALTER DATABASE [dvbbs] SET MULTI_USER W6NhJ#M7
GO !6=;dX
7、日志清除 &|GH@^)@
SET NOCOUNT ON DX>LB$dy?
DECLARE @LogicalFileName sysname,
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@MaxMinutes INT, -@"3`uv"
@NewSize INT [+dCA
USE tablename -- 要操作的数据库名 O@a OKk
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~Dq-q6-@t
@MaxMinutes = 10, -- Limit on time allowed to wrap log. q| 1%G Nb
@NewSize = 1 -- 你想设定的日志文件的大小(M) Q!@M/@-Ky
-- Setup / initialize E2>{se Z
DECLARE @OriginalSize int K?'m#}]
SELECT @OriginalSize = size )2?]c
FROM sysfiles -^CW}IM{ I
WHERE name = @LogicalFileName w!6{{m
SELECT 'Original Size of ' + db_name() + ' LOG is ' + sPvs}}Z]P
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + mB_?N $K
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' pxTtV g.
FROM sysfiles ;QXg*GNAv$
WHERE name = @LogicalFileName P(k*SB|D
CREATE TABLE DummyTrans $`3yImv+w
(DummyColumn char (8000) not null) n~ad#iN
DECLARE @Counter INT, `~)?OTzU#
@StartTime DATETIME, ?DUim1KG
@TruncLog VARCHAR(255) #RR;?`,L}
SELECT @StartTime = GETDATE(), t"GnmeH
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,W)DQwAg
DBCC SHRINKFILE (@LogicalFileName, @NewSize) |JIlp"[
EXEC (@TruncLog) ZL<X*l2
-- Wrap the log if necessary. F8-GnTxa
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %"mI["{
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) q *&H
AND (@OriginalSize * 8 /1024) > @NewSize c8X;4
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BEGIN -- Outer loop. ]j>xQm\
SELECT @Counter = 0 uK" T~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) oqF?9<Vgc,
BEGIN -- update % akW43cE
INSERT DummyTrans VALUES ('Fill Log') GuR^L@+ -.
DELETE DummyTrans PzSLE>Q
SELECT @Counter = @Counter + 1 {TNORbZz
END U,i_}O3Q
EXEC (@TruncLog) (yP1}?
END kiM:(=5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + LP#wE~K"b
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,M3hE/rb/
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3(V0,L'1
FROM sysfiles qo3+=*"V
WHERE name = @LogicalFileName -fA =&$V
DROP TABLE DummyTrans >B0AJW/u
SET NOCOUNT OFF P".}Y[GD
8、说明:更改某个表 vK)'3%
exec sp_changeobjectowner 'tablename','dbo' 6}E>B{Y
9、存储更改全部表 yk?bz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch qG;tD>jy
@OldOwner as NVARCHAR(128), =|E
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@NewOwner as NVARCHAR(128) 5eff3qrH{
AS BC.3U.
DECLARE @Name as NVARCHAR(128) p"%D/-%Gu
DECLARE @Owner as NVARCHAR(128) qBBCnT
DECLARE @OwnerName as NVARCHAR(128) g8MW6Y
DECLARE curObject CURSOR FOR u:p OP
select 'Name' = name, )]C]K B
'Owner' = user_name(uid) rk1,LsZVS
from sysobjects #E!^oZm<Z
where user_name(uid)=@OldOwner %oa@2qJ^
order by name GO"|^W
OPEN curObject bfz7t!A)A
FETCH NEXT FROM curObject INTO @Name, @Owner ,1mL=|na
WHILE(@@FETCH_STATUS=0) -z`%x@F<&L
BEGIN qF~9:`
if @Owner=@OldOwner $f3 IO#N
begin <)T| HKx
set @OwnerName = @OldOwner + '.' + rtrim(@Name) k^%=\c
exec sp_changeobjectowner @OwnerName, @NewOwner LhLAQ2~
end ; H ;h[
-- select @name,@NewOwner,@OldOwner /lC# !$9vz
FETCH NEXT FROM curObject INTO @Name, @Owner +I3Vfv
END Q ")Xg:
close curObject >IaGa!4
deallocate curObject gf8o~vKX$G
GO %evb.h)
10、SQL SERVER中直接循环写入数据 aNu.4c/5
declare @i int I^k&v V
set @i=1 @)h>vg
while @i<30 Yg.[R]
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begin HZ'rM5Kq
insert into test (userid) values(@i) F@Sk=l(
set @i=@i+1 z<5 5[~3
end F&wAre<
小记存储过程中经常用到的本周,本月,本年函数 mh}D[K=~%
Dateadd(wk,datediff(wk,0,getdate()),-1) sn:VM HrOT
Dateadd(wk,datediff(wk,0,getdate()),6) j_g(6uZhz3
Dateadd(mm,datediff(mm,0,getdate()),0) 6m?<"y8]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) XF(D%ygeC
Dateadd(yy,datediff(yy,0,getdate()),0) c0Ih$z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) s_y8+BJaV
上面的SQL代码只是一个时间段 vcu@_N 1Dc
Dateadd(wk,datediff(wk,0,getdate()),-1) KuJ9bn{u!C
Dateadd(wk,datediff(wk,0,getdate()),6) UPGUJ>2Z
就是表示本周时间段.
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下面的SQL的条件部分,就是查询时间段在本周范围内的: >rQj1D)@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) D{JjSky
而在存储过程中 l-%] f]>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1=J& ^O{W
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?:$
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