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。 xpKD 'O=T
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一、基础 z"u4t.KpL
1、说明:创建数据库 mZDrvTI'
CREATE DATABASE database-name [7ZFxr\:!
2、说明:删除数据库 =GTltFqI1
drop database dbname GNA:|x
3、说明:备份sql server Rgw\qOb
--- 创建 备份数据的 device gXZ.je)NM
USE master d%\{,
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0R>M_|
--- 开始 备份 [iwn"e
BACKUP DATABASE pubs TO testBack [bIdhG
4、说明:创建新表 *T*=~Y4kE
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `$jc=ZLm
根据已有的表创建新表: VJS|H!CH
A:create table tab_new like tab_old (使用旧表创建新表) :seo0w]
B:create table tab_new as select col1,col2... from tab_old definition only cXFNX<
5、说明:删除新表 0
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drop table tabname p\wE})mu
6、说明:增加一个列 # nwEF QA
Alter table tabname add column col type 3<1Uq3Pa
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 w-2p'u['Z
7、说明:添加主键: Alter table tabname add primary key(col) ns9iTU)
说明:删除主键: Alter table tabname drop primary key(col) znw\Dn?g
8、说明:创建索引:create [unique] index idxname on tabname(col....) 'xm _oGWE
删除索引:drop index idxname SG2s!Ht
注:索引是不可更改的,想更改必须删除重新建。 ~EG`[cv
9、说明:创建视图:create view viewname as select statement {O*WLZ {0
删除视图:drop view viewname "GEJ9_a[
10、说明:几个简单的基本的sql语句 h!?7I=p~#
选择:select * from table1 where 范围 N0oBtGb
插入:insert into table1(field1,field2) values(value1,value2) t>. mB@se|
删除:delete from table1 where 范围 d_BECx<\
更新:update table1 set field1=value1 where 范围 YgNt>4K
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^]3Y11sI
排序:select * from table1 order by field1,field2 [desc] rP>iPDf
总数:select count as totalcount from table1 5m!FtHvm1
求和:select sum(field1) as sumvalue from table1 //nR=Dy{
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 >t&Frw/Bl
最小:select min(field1) as minvalue from table1 `$\g8Mo
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11、说明:几个高级查询运算词 "~0m_brf
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A: UNION 运算符 Jp=eh
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。 ME7jF9d
B: EXCEPT 运算符 tI0d!8K
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。 1T a48
C: INTERSECT 运算符 `9n%Dy<
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。 s]Nh9h
注:使用运算词的几个查询结果行必须是一致的。 oA%8k51>~K
12、说明:使用外连接 m!3b.2/h
A、left outer join: BoE;,s>]NW
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。 y8'WR-;
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 $@"o BCc
B:right outer join: yT%"<m6Y*\
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 >!MOgLO3
C:full outer join: ?F1NZA[%t
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 oMawINDa
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二、提升 4n @}X-)
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) zV_U/]y
法一:select * into b from a where 1<>1 'VcZ_m:
法二:select top 0 * into b from a ^I=c]D]);
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) !qsk;Vk7Z
insert into b(a, b, c) select d,e,f from b; (xf_
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 5@ecZ2`)+h
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mD{<Lp=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) u[q1]]
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) -B-?z?+(O
5、说明:显示文章、提交人和最后回复时间 YjN2 ,Xi
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) 4nQk*:p(X
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c i_Dv+^&zV
7、说明:在线视图查询(表名1:a ) WL$nchS9
select * from (SELECT a,b,c FROM a) T where t.a > 1; v!n\A}^:
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 d0$dQg
select * from table1 where time between time1 and time2 23 j{bK
select a,b,c, from table1 where a not between 数值1 and 数值2 ~N2){0j4
9、说明:in 的使用方法 j&6'sg;n)
select * from table1 where a [not] in ('值1','值2','值4','值6') qP{S!Z(
10、说明:两张关联表,删除主表中已经在副表中没有的信息 C` ?6`$Y
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) S*-n%D0q5
11、说明:四表联查问题: k~Qb"6n2
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 ..... 83~
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12、说明:日程安排提前五分钟提醒 DG,CL8bv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 kY*3)KCp
13、说明:一条sql 语句搞定数据库分页 \]ouQR.t@\
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 z/6/
14、说明:前10条记录 Dnn$-W|NC
select top 10 * form table1 where 范围 gKy@$at&
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.) VU3xP2c:
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) v- M3/*
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 b fy `UZr
(select a from tableA ) except (select a from tableB) except (select a from tableC) ngJi;9X8*t
17、说明:随机取出10条数据 >=Hm2daN
select top 10 * from tablename order by newid() D%GB2-j R
18、说明:随机选择记录 3mKmd iD
select newid() /nEt%YYh;x
19、说明:删除重复记录 mL/]an@Y
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 7hwl[knyB
20、说明:列出数据库里所有的表名 =<mpZ'9gW
select name from sysobjects where type='U' lc9aDt
21、说明:列出表里的所有的 gdkl,z3N3
select name from syscolumns where id=object_id('TableName') b*Ny
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。 gZ%wmY
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 iJ.P&T9
显示结果: eAKK uML
type vender pcs R|aA6} /I
电脑 A 1 n!=%MgF'*p
电脑 A 1 H }w"4s
光盘 B 2 ReE-I/n8f
光盘 A 2 '{=dEEi
手机 B 3 5N
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手机 C 3 gM_z`H5[!
23、说明:初始化表table1 R\k=
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TRUNCATE TABLE table1 $ZX^JWq
24、说明:选择从10到15的记录 F F<xsoZJ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KNT(lA0s
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三、技巧 N!Dc\d=8q]
1、1=1,1=2的使用,在SQL语句组合时用的较多 \l!^6G|c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \`?#V xz
如: .3WDtVE
if @strWhere !='' EWuuNf
begin x xxM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _/;k;$gDp
end &'`q&U1x
else Vj?{T(K1[
begin M`IiK+IoU
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' E^uau=F
end '}\{4Qst
我们可以直接写成 "q@OMf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere lrSdFJ%
2、收缩数据库 {TT@Mkz_QC
--重建索引 6&/H
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DBCC REINDEX p;Ezmz
DBCC INDEXDEFRAG b]S4\BBT
--收缩数据和日志 .b]
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DBCC SHRINKDB xbJ@ z{
DBCC SHRINKFILE `H+~LVH
3、压缩数据库 _22;hnG<iy
dbcc shrinkdatabase(dbname) me]O
4、转移数据库给新用户以已存在用户权限 Y"qKe,
exec sp_change_users_login 'update_one','newname','oldname' Uw R,U#d
go ghvF%-."1
5、检查备份集 DVCO(
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' L B`=+FD
6、修复数据库 }G^Bc4@b
ALTER DATABASE [dvbbs] SET SINGLE_USER bg.f';C
GO XE8~R5
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?DPNa
GO 2 mM0\ja
ALTER DATABASE [dvbbs] SET MULTI_USER :NB|r
GO v%RcwVt|
7、日志清除 9^l[d<
SET NOCOUNT ON ;0*T7l
DECLARE @LogicalFileName sysname, 9y=$|"<(
@MaxMinutes INT, K07SbL7g!p
@NewSize INT _nw=^zS
USE tablename -- 要操作的数据库名 {SH+lX0]{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z9-HQ5>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. mq~rD)T
@NewSize = 1 -- 你想设定的日志文件的大小(M) GE4d=;5
-- Setup / initialize -$Bom
DECLARE @OriginalSize int tBEZ4 W>67
SELECT @OriginalSize = size zrfE'C8O
FROM sysfiles ' k~'aZ
WHERE name = @LogicalFileName \m @8$MK
SELECT 'Original Size of ' + db_name() + ' LOG is ' + b|U48j1A
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :x e/7 -
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &sbA:xZBA
FROM sysfiles \(UEjlo
WHERE name = @LogicalFileName GCx1lm
CREATE TABLE DummyTrans #PYTFB%
(DummyColumn char (8000) not null) G<.p".o4
DECLARE @Counter INT, GRpS^%8i@
@StartTime DATETIME, hpJ[VKe
@TruncLog VARCHAR(255) MGn:Gj"d
SELECT @StartTime = GETDATE(), 9/Q_Jv-Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Bkg/A;H
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U" eP>HHp
EXEC (@TruncLog) Id8^6FLw
-- Wrap the log if necessary. $Yfm>4
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired `q Sfo`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }\5^$[p
AND (@OriginalSize * 8 /1024) > @NewSize cVv>"oF;~*
BEGIN -- Outer loop. G=4Da~<ij
SELECT @Counter = 0 1_vaSEov
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) jJ%
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BEGIN -- update f(q^R
INSERT DummyTrans VALUES ('Fill Log') `5}XmSJ?5
DELETE DummyTrans $LUNA.
SELECT @Counter = @Counter + 1 h>B>t/k?
END +gb2>fei&
EXEC (@TruncLog) /7Z0|Zw]
END #5HJW[9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + c_b^t09
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?8wFT!J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' (:3rANY|
FROM sysfiles CL/8p;
WHERE name = @LogicalFileName _%Q\G,a;
DROP TABLE DummyTrans )fSQTbB;0
SET NOCOUNT OFF -L7Q,"a$
8、说明:更改某个表 (bH*i\W
exec sp_changeobjectowner 'tablename','dbo' [sG=(~BU
9、存储更改全部表 U(5(0r
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch w?kdM1T
@OldOwner as NVARCHAR(128), Zcd!y9]#
@NewOwner as NVARCHAR(128) 31mY]Jve"
AS ,lm.~% }P*
DECLARE @Name as NVARCHAR(128) e#`wshtN:
DECLARE @Owner as NVARCHAR(128) 4)Y=)#=
DECLARE @OwnerName as NVARCHAR(128) W2h^ShG
DECLARE curObject CURSOR FOR 061@N=p8
select 'Name' = name, <~# ZtD$G
'Owner' = user_name(uid) ` +]9+:tS
from sysobjects !?B9 0(
where user_name(uid)=@OldOwner fx|$(D@9
order by name l= 5kd.{
OPEN curObject R{S{N2+p(
FETCH NEXT FROM curObject INTO @Name, @Owner M@@"-dy
WHILE(@@FETCH_STATUS=0) bG
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BEGIN 2GECcx53
if @Owner=@OldOwner c0ET]
begin K V^`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) hnS
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exec sp_changeobjectowner @OwnerName, @NewOwner $oK,&_
end Vf6lu)Zc1
-- select @name,@NewOwner,@OldOwner mJb>)bOl
FETCH NEXT FROM curObject INTO @Name, @Owner "PGEiLY
END ==I:>+_^|
close curObject _5#f9,m1
deallocate curObject #9z\Wblr
GO ry}CND(nB
10、SQL SERVER中直接循环写入数据 Vea>T^
declare @i int !pl<
set @i=1 *{:FPmDU
while @i<30 xin<.)!E
begin (A`/3Aq+
insert into test (userid) values(@i) M$A"<5
set @i=@i+1 e#L/
end 7dI+aJ
小记存储过程中经常用到的本周,本月,本年函数 Sj{z
Dateadd(wk,datediff(wk,0,getdate()),-1) 0[}"b(O{
Dateadd(wk,datediff(wk,0,getdate()),6) Md'd=Y_0
Dateadd(mm,datediff(mm,0,getdate()),0) 5T}$+R0&
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kV"';a
Dateadd(yy,datediff(yy,0,getdate()),0) m *8[I
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) O?NAbxkp
上面的SQL代码只是一个时间段 @u3K.}i:g
Dateadd(wk,datediff(wk,0,getdate()),-1) |0n h
Dateadd(wk,datediff(wk,0,getdate()),6) l epR}
就是表示本周时间段. ->&AJI0
下面的SQL的条件部分,就是查询时间段在本周范围内的: 2J rr;"r
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %*]3j^b Q+
而在存储过程中 %YefTk8cr,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) uc~PKU?tO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) D8slSX`6j