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。 M:t"is
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一、基础 7`SrqI&
1、说明:创建数据库 )W>9{*4m
CREATE DATABASE database-name W)Mc$`nX
2、说明:删除数据库 \{54mM~
drop database dbname 2+|U!X
3、说明:备份sql server [bjP-pX
--- 创建 备份数据的 device Mo]
USE master >2mV{i&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8u"HW~~=
--- 开始 备份 (H-kWT
BACKUP DATABASE pubs TO testBack 3-gy)5.xe
4、说明:创建新表 pE6r7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) w
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根据已有的表创建新表: >
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A:create table tab_new like tab_old (使用旧表创建新表) g:?p/L
B:create table tab_new as select col1,col2... from tab_old definition only v\R-G
5、说明:删除新表 Z`>m
drop table tabname k<
6、说明:增加一个列 Q+dLWFI
Alter table tabname add column col type +0M0g_sk
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。 R0T{9,;[`
7、说明:添加主键: Alter table tabname add primary key(col) S'=}eeG
说明:删除主键: Alter table tabname drop primary key(col) I[P_j`aE
8、说明:创建索引:create [unique] index idxname on tabname(col....) -_irkpdC[
删除索引:drop index idxname [{6fyd;
注:索引是不可更改的,想更改必须删除重新建。 c Qq78Lo
9、说明:创建视图:create view viewname as select statement sfs2ki H
删除视图:drop view viewname QW2SFpE
10、说明:几个简单的基本的sql语句 N^zFKDJG
选择:select * from table1 where 范围 c:2LG_mQ
插入:insert into table1(field1,field2) values(value1,value2) 2I{kLN1TY
删除:delete from table1 where 范围 Sw`+4
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更新:update table1 set field1=value1 where 范围 9
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )pG*_q
排序:select * from table1 order by field1,field2 [desc] Xn%O .yM6
总数:select count as totalcount from table1 r tH
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求和:select sum(field1) as sumvalue from table1 TiD|.a8S
平均:select avg(field1) as avgvalue from table1 2 @t?@,c
最大:select max(field1) as maxvalue from table1 3+H[S#e:Z
最小:select min(field1) as minvalue from table1 B[fbP rM
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11、说明:几个高级查询运算词 j{Sbf04
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A: UNION 运算符 f'OcW*t
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。 &[_D'jm+S0
B: EXCEPT 运算符 NB3ar&.$S
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。 O T .bXr~
C: INTERSECT 运算符 !G;|~|fMV
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。 VCa`|S?2
注:使用运算词的几个查询结果行必须是一致的。 kn}bb*eZ
12、说明:使用外连接 2j=HxE
A、left outer join: !%/(a)B$^$
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。 9}'92
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 BB.120v&N
B:right outer join: ,y gDNF
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。 :]9CdkaU
C:full outer join: x57O.WdN
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。 z4JhLef %
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二、提升 ;nKhmcQ4
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ;:'A Bfs
法一:select * into b from a where 1<>1 ~=?^v[T1
法二:select top 0 * into b from a WP
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \6;b.&%w2
insert into b(a, b, c) select d,e,f from b; .7> g8
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) E6#")2C~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |N:kf&]b
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. R{q<V uN
4、说明:子查询(表名1:a 表名2:b) fk\hrVP
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) *kt%.wPJ
5、说明:显示文章、提交人和最后回复时间 3V3 q
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 76b2 3|
6、说明:外连接查询(表名1:a 表名2:b) duoM>B>8]
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <%S[6*6U
7、说明:在线视图查询(表名1:a ) p+16*f9,^
select * from (SELECT a,b,c FROM a) T where t.a > 1; oo]g=C$n
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 QsyM[; \j:
select * from table1 where time between time1 and time2 rmPJid[8B~
select a,b,c, from table1 where a not between 数值1 and 数值2 x/IAc6H~_8
9、说明:in 的使用方法 C^*}*hYk$
select * from table1 where a [not] in ('值1','值2','值4','值6') @^nE^;
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /`g~lww2O
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) k]S`A,~
11、说明:四表联查问题: )5w# n1
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 ..... wc?YzXP+
12、说明:日程安排提前五分钟提醒 0[Z wtfL1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Aq_?8 Cd
13、说明:一条sql 语句搞定数据库分页 T 2Gscey
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 +HoCG;C{
14、说明:前10条记录 p?sFX$S
select top 10 * form table1 where 范围 *ch7z|wo.
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Y/qs\c+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @Op7OFY%
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 'S6JpWG1
(select a from tableA ) except (select a from tableB) except (select a from tableC) hlFvm$P`M
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() pI}6AAs}Z
18、说明:随机选择记录 ab>>W!r@!
select newid() b;"Z`/h
19、说明:删除重复记录 m*` W&k[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) z W*Z
20、说明:列出数据库里所有的表名 X9o6} %Y
select name from sysobjects where type='U' L+.-aB2!d
21、说明:列出表里的所有的 !uAqY\Is
select name from syscolumns where id=object_id('TableName') W&e}*
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。 ~U1M-<IX
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 D4PjE@D"H
显示结果: fDKV`
type vender pcs 0134mw%jk
电脑 A 1 iV.j!H7o
电脑 A 1 (`&E^t
光盘 B 2 ah15,<j
光盘 A 2 Jf@~/!m}'
手机 B 3 InB'Ag"
手机 C 3 7xCm"jgP
23、说明:初始化表table1 !z"nJC
TRUNCATE TABLE table1 zUz j
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24、说明:选择从10到15的记录 7t|011<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc SD]rYIu+
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三、技巧 )\QPUdOvx
1、1=1,1=2的使用,在SQL语句组合时用的较多 U_@Dn[/:
"where 1=1" 是表示选择全部 "where 1=2"全部不选, TH? wXd\
如: xQ>T.nP}1
if @strWhere !='' ""x>-j4
begin 9&'HhJm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sQ8kLS_q8
end KvtJtql;
else qw}.
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begin [ Ru( H
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Lo5CVlK
end Sj@VOW
我们可以直接写成 %)P)Xb
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }/}eZCaG
2、收缩数据库 "eR-(c1
--重建索引 nD#uOep9
DBCC REINDEX &6\f;T4
DBCC INDEXDEFRAG {1[f9uPS
--收缩数据和日志 0EBHRY_F
DBCC SHRINKDB I$JyAj
DBCC SHRINKFILE 1|oE3
3、压缩数据库 jF|LPWl
dbcc shrinkdatabase(dbname) /gq\.+'{
4、转移数据库给新用户以已存在用户权限 /H :Bu
exec sp_change_users_login 'update_one','newname','oldname' _t@9WA;+\
go 2R~[B]2"r
5、检查备份集 A\QrawBp0l
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -\V;Gw8mD
6、修复数据库 * a@78&N
ALTER DATABASE [dvbbs] SET SINGLE_USER |jyD@Q,4
GO %QFeQ(b/(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A4f;ftB
GO Y!3i3D
ALTER DATABASE [dvbbs] SET MULTI_USER 'Jl3%axR
GO 9[Xe|5?c
7、日志清除 JwcC9
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SET NOCOUNT ON ]QmY`pTB`
DECLARE @LogicalFileName sysname, 'Ad |*~
@MaxMinutes INT, PAs.T4Av^
@NewSize INT CC XOxd
USE tablename -- 要操作的数据库名 dyuT-.2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \\$wg
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !-s 6B
@NewSize = 1 -- 你想设定的日志文件的大小(M) d2tJ=.DI
-- Setup / initialize qaEWK0
DECLARE @OriginalSize int
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SELECT @OriginalSize = size trM)&aQto
FROM sysfiles og8"#%
WHERE name = @LogicalFileName ;N!W|G
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + LGPg\g`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' A:,R.P>`C
FROM sysfiles -ZBSkyMGy
WHERE name = @LogicalFileName XMm(D!6
CREATE TABLE DummyTrans wPH1g*U
(DummyColumn char (8000) not null) & 6~AY:0r
DECLARE @Counter INT, Mx=L lC)
@StartTime DATETIME, [:cZDVaA|
@TruncLog VARCHAR(255) 6|ENDd[
SELECT @StartTime = GETDATE(), x<h-F
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Nt_7Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) -0Q^k\X-
EXEC (@TruncLog) >@L^^-r
-- Wrap the log if necessary. -mqTlXM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~:):.5o
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) q%c"`u/v/
AND (@OriginalSize * 8 /1024) > @NewSize 7G9o%!D5
BEGIN -- Outer loop. e%.|PZ)
SELECT @Counter = 0 LKI2R_|n
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Nzel^~
BEGIN -- update :qO)^~x
INSERT DummyTrans VALUES ('Fill Log') H&=3rkX
DELETE DummyTrans h} <Ie <
SELECT @Counter = @Counter + 1 n]J;BW&Av
END ~OOD#/
EXEC (@TruncLog) >d#Ks0\&
END _-bEnF+/0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~Is-^k)y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e*jfxQ=qG
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1[H1l;
FROM sysfiles ?)'+l
WHERE name = @LogicalFileName Pqb])-M9p
DROP TABLE DummyTrans bAm ,gP
SET NOCOUNT OFF -
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8、说明:更改某个表 %<Kw
exec sp_changeobjectowner 'tablename','dbo' i 79;;9M
9、存储更改全部表 wNhtw'E8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), DJ<F8-sb2r
@NewOwner as NVARCHAR(128) PR*qyELu
AS Y)OTvKrOA
DECLARE @Name as NVARCHAR(128) BSbi.@@tp
DECLARE @Owner as NVARCHAR(128) UA$Xa1
DECLARE @OwnerName as NVARCHAR(128) 6qp'
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DECLARE curObject CURSOR FOR Hy0l"CA*|
select 'Name' = name, osW"b"_f
'Owner' = user_name(uid) TNK~ETE4
from sysobjects k4Ub+F
where user_name(uid)=@OldOwner -p2 =?a
order by name r-k,4Yz
OPEN curObject 3tIno!|
FETCH NEXT FROM curObject INTO @Name, @Owner mYiIwm1cb(
WHILE(@@FETCH_STATUS=0) VN!+r7w'
BEGIN +^v]d_~w_
if @Owner=@OldOwner CPS1b
begin Zfub+A
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8WvQ[cd
exec sp_changeobjectowner @OwnerName, @NewOwner ,.T k"\@
end lL{1wCsl
-- select @name,@NewOwner,@OldOwner j[y,Jch
FETCH NEXT FROM curObject INTO @Name, @Owner 8{iFxTz
END " .:b43Z
close curObject FfR%@
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deallocate curObject #_}r)q
GO &H<n76G
10、SQL SERVER中直接循环写入数据 9#A&Qvyywg
declare @i int M~k2Y$}R
set @i=1 y%^TZ[S
while @i<30 TB
begin a]mPc^h
insert into test (userid) values(@i) eLc@w<yB
set @i=@i+1 ui#K`.dn
end (<:mCPk(~
小记存储过程中经常用到的本周,本月,本年函数 _onEXrM
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) ~56F<=#,
Dateadd(mm,datediff(mm,0,getdate()),0) :VEy\ R>W
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) z'+k]N9Q^
Dateadd(yy,datediff(yy,0,getdate()),0) 'E#;`}&Ah
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ek3,ss3
上面的SQL代码只是一个时间段 Sx^4Y\\
Dateadd(wk,datediff(wk,0,getdate()),-1) !O-9W=NJ
Dateadd(wk,datediff(wk,0,getdate()),6) A(#4$}!n5
就是表示本周时间段. '7Aj0U(
下面的SQL的条件部分,就是查询时间段在本周范围内的: o/Cu^[an
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Jm(sx'qPx
而在存储过程中 _x ;fTW0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) C@8WY
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) JIobs*e0m