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。 vvxxwZa=O
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一、基础 #`SAc`:n
1、说明:创建数据库 WzzA:X
CREATE DATABASE database-name px;~20$e
2、说明:删除数据库 7:UeE~uB:
drop database dbname AIHH@z
3、说明:备份sql server WESD^FK
--- 创建 备份数据的 device [7@blU
USE master *Dp&;, b
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2y!n c%
--- 开始 备份 zVE" 6
BACKUP DATABASE pubs TO testBack 3WwS+6R
4、说明:创建新表 E^-c,4'F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [piK"N
根据已有的表创建新表: )g:5}+
A:create table tab_new like tab_old (使用旧表创建新表) zB%~=@Q^6
B:create table tab_new as select col1,col2... from tab_old definition only $wM..ee
5、说明:删除新表 JO|j?%6YY
drop table tabname (>}1t!1
6、说明:增加一个列 q2%cLbI
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Alter table tabname add column col type ]t0o%w
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 }U7IMONU
7、说明:添加主键: Alter table tabname add primary key(col) )q<VZ|V
说明:删除主键: Alter table tabname drop primary key(col) s\d3u`G
8、说明:创建索引:create [unique] index idxname on tabname(col....) 5p.rd0T]l3
删除索引:drop index idxname ~ikp'5
注:索引是不可更改的,想更改必须删除重新建。 K\-N'M!Z
9、说明:创建视图:create view viewname as select statement 1L<TzQ
删除视图:drop view viewname j([b)k=
10、说明:几个简单的基本的sql语句 a#1r'z~]}
选择:select * from table1 where 范围 .w4|$.H
插入:insert into table1(field1,field2) values(value1,value2) H
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删除:delete from table1 where 范围 +Ug &
更新:update table1 set field1=value1 where 范围 8ve-g\C8 H
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! s`x2Go
排序:select * from table1 order by field1,field2 [desc] 0s`6d;
总数:select count as totalcount from table1 S\Z*7j3;M
求和:select sum(field1) as sumvalue from table1 gxhp7c182
平均:select avg(field1) as avgvalue from table1 w^L`"
最大:select max(field1) as maxvalue from table1 0@_8JB ?E
最小:select min(field1) as minvalue from table1 S:!5|o|
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11、说明:几个高级查询运算词 ;*5z&1O
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A: UNION 运算符 Z(:\Vj"
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。 K14.!m
B: EXCEPT 运算符 bN?*p($/
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。 lsV>sW4]Z
C: INTERSECT 运算符 -}@C9Ja[?
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。 f.ua,,P.
注:使用运算词的几个查询结果行必须是一致的。 >0kL9_9{
12、说明:使用外连接 oxFd@WV5
A、left outer join: 70avr)OM
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。 jGLmgJG-P
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 y2%[/L:u~
B:right outer join: TFbc@rfB
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。 5@.8O VPz
C:full outer join: ^/2O_C
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。 ++2a xRl
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二、提升 \.P'8As
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) '(ETXQ@
法一:select * into b from a where 1<>1 k;umLyz
法二:select top 0 * into b from a Uwiy@T Z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) eJOo~HIWQ
insert into b(a, b, c) select d,e,f from b; (4l M3clF
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) 9Lt3^MKa"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 YbVZK4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. mznE Cy
4、说明:子查询(表名1:a 表名2:b) ;XY#Jl>tg
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) I<lkociUCG
5、说明:显示文章、提交人和最后回复时间 #r&yH^-
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b N*w{NB 7L
6、说明:外连接查询(表名1:a 表名2:b) i/N6 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 :)_P7k`>e/
7、说明:在线视图查询(表名1:a ) UL8"{-`_\
select * from (SELECT a,b,c FROM a) T where t.a > 1; ue
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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 pv|D{39Hs
select * from table1 where time between time1 and time2 ({rescQB
select a,b,c, from table1 where a not between 数值1 and 数值2 TAM`i3{ D
9、说明:in 的使用方法 r-BqIoVT
select * from table1 where a [not] in ('值1','值2','值4','值6') P`hg*"<V
10、说明:两张关联表,删除主表中已经在副表中没有的信息 $I@. <J*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) M>Ws}Y
11、说明:四表联查问题: D>#Jh>4
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... kJXy)
12、说明:日程安排提前五分钟提醒 Re\V<\$J
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "'8o8g
13、说明:一条sql 语句搞定数据库分页 o AS 'Z|
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ?IG+U TI
14、说明:前10条记录 AQBr{^inH|
select top 10 * form table1 where 范围 /i~n**HeF?
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) +fF4]WFP
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) h8SK8sK<
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 cMt
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(select a from tableA ) except (select a from tableB) except (select a from tableC) .9bP8u2B{
17、说明:随机取出10条数据 l$p"%5]_
select top 10 * from tablename order by newid() Yi"jj;!^S
18、说明:随机选择记录 =dC5q{
select newid() Vzrp9&loY
19、说明:删除重复记录 $uNYus^vS
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "6'# L,
20、说明:列出数据库里所有的表名 o@\q 6xl.
select name from sysobjects where type='U' rUF= uO(
21、说明:列出表里的所有的 [=xO>
select name from syscolumns where id=object_id('TableName') 8J7<7Sx
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。 /?8rj3
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 *}i.,4+y
显示结果: b!|c:mE9|
type vender pcs 0jwex
电脑 A 1 *$7c||J7
电脑 A 1 $5l=&
光盘 B 2 ,}#l0BY
光盘 A 2 yX8$LOjE
手机 B 3 A[oxG;9xi
手机 C 3 0~XZ
23、说明:初始化表table1 n.xW"omN
TRUNCATE TABLE table1 q>ps99[=
24、说明:选择从10到15的记录 6d3-GMUQ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc rOy-6og
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三、技巧 DPZG_{3D
1、1=1,1=2的使用,在SQL语句组合时用的较多 "h}miVArS
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ON=6w_
如: tcf>9YsOr
if @strWhere !='' 4HK#]M>yz
begin Hh8)d/D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4`7:gfrO,
end <OEu 4,~:
else G? "6[w/p
begin q~=]_PMP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 0Y9\,y_
end RscU=oaKi
我们可以直接写成 5[Yzi> o[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Hb;#aXHSd
2、收缩数据库 #yv_Eb02
--重建索引 TnqspS2;R
DBCC REINDEX *s9
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DBCC INDEXDEFRAG d-=/@N!4e
--收缩数据和日志 jR#g>MDKB
DBCC SHRINKDB x\Bl^1&
DBCC SHRINKFILE <o";?^0Q
3、压缩数据库 G.,dP+i
dbcc shrinkdatabase(dbname) H1>}E5^?
4、转移数据库给新用户以已存在用户权限 hp]T ^
exec sp_change_users_login 'update_one','newname','oldname' S&% GB
go kmm1b (
5、检查备份集 .R` {.~_{!
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' uFIr.U$V
6、修复数据库 &oTUj'$
ALTER DATABASE [dvbbs] SET SINGLE_USER brGUK PB
GO MkG3TODfHB
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK < 6[XE
GO 5uuZ t0V\
ALTER DATABASE [dvbbs] SET MULTI_USER Q&;dXE h
GO `Li3=!V[
7、日志清除 V6Y:l9
SET NOCOUNT ON F`;oe[wfk
DECLARE @LogicalFileName sysname, mVN^X/L(y
@MaxMinutes INT, [ 44d(P'
@NewSize INT .AOf-a
USE tablename -- 要操作的数据库名 ~r6qnC2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Tp&03
@MaxMinutes = 10, -- Limit on time allowed to wrap log. C#`VVtei
@NewSize = 1 -- 你想设定的日志文件的大小(M) NuKktQd
-- Setup / initialize 'PF?D~
DECLARE @OriginalSize int s88lN=;
SELECT @OriginalSize = size n5X0Gi9
FROM sysfiles X|)Ox
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WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + hmv"|1Sa!~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Iq`:h&'!L
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f\FubL
FROM sysfiles 9pD=E>4?#
WHERE name = @LogicalFileName }u0t i"V
CREATE TABLE DummyTrans Bkvh]k;F8
(DummyColumn char (8000) not null) qh!2dj
DECLARE @Counter INT, Np=IZnpt
@StartTime DATETIME, mdW8RsR
@TruncLog VARCHAR(255) V8w!yc
SELECT @StartTime = GETDATE(), |-l)$i@
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %Ji@\|Zkf
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 8|uFW7Q
EXEC (@TruncLog) ^T83E}
-- Wrap the log if necessary. vq|o}6Et
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T> cvV
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =^m,|j|d>4
AND (@OriginalSize * 8 /1024) > @NewSize &o>ctf.x
BEGIN -- Outer loop. *Y'@|xf*
SELECT @Counter = 0 JyY-@GF
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Mvq5s +.
BEGIN -- update M}E0Msq_o
INSERT DummyTrans VALUES ('Fill Log') 47b=>D8
DELETE DummyTrans g/&`NlD
SELECT @Counter = @Counter + 1 *6oQW
END m0+X 109
EXEC (@TruncLog) :|3n`,
END O)78
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + _Gv[ D
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + j_\nsM7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' qi7(RL_N
FROM sysfiles rnvKfTpZDU
WHERE name = @LogicalFileName @0cQ4}
DROP TABLE DummyTrans #%t&f"j2
SET NOCOUNT OFF og<mFbqkq7
8、说明:更改某个表 C
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exec sp_changeobjectowner 'tablename','dbo' M}|<#
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9、存储更改全部表 dYdZt<6W<(
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch t{n|!T&
@OldOwner as NVARCHAR(128), Ergh]"AD6-
@NewOwner as NVARCHAR(128) RO(~c-fV
AS f$vWi&(
DECLARE @Name as NVARCHAR(128) e|)6zh<O:
DECLARE @Owner as NVARCHAR(128) >CtT_yhx
DECLARE @OwnerName as NVARCHAR(128) C'mYR3?m;
DECLARE curObject CURSOR FOR 5}d"nx
select 'Name' = name, gPs%v`y)*D
'Owner' = user_name(uid) vovc,4}
from sysobjects #p@8m_g
where user_name(uid)=@OldOwner $\BRX\6(-
order by name \ 8v{9Yb
OPEN curObject /,v>w,
FETCH NEXT FROM curObject INTO @Name, @Owner wg<UCmfu!
WHILE(@@FETCH_STATUS=0) %$K2$dq5
BEGIN Y0`@$d&n
if @Owner=@OldOwner o RT<h
begin W`HO Q
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7?Vo([8
exec sp_changeobjectowner @OwnerName, @NewOwner %Q9
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end y5;l?v94
-- select @name,@NewOwner,@OldOwner CG!/Lbd
FETCH NEXT FROM curObject INTO @Name, @Owner tmM8YN|
END Jj=0{(X
close curObject M{ #
deallocate curObject $F V!HD
GO x8H%88!j*
10、SQL SERVER中直接循环写入数据 5fpBzn$
declare @i int .I%p0ds1r
set @i=1 6")co9
while @i<30 'Oyx
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begin ub^v,S8O
insert into test (userid) values(@i) fNz*E|]8&
set @i=@i+1 _2*Ryz
end a o_A%?Ld
小记存储过程中经常用到的本周,本月,本年函数 n^OWz4
Dateadd(wk,datediff(wk,0,getdate()),-1) DoV<p?U
Dateadd(wk,datediff(wk,0,getdate()),6) HD"Pz}k4
Dateadd(mm,datediff(mm,0,getdate()),0) mQ#E{{:H+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) CS[[TzC=5
Dateadd(yy,datediff(yy,0,getdate()),0) \Kh@P*7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \@]/ks=K
上面的SQL代码只是一个时间段 9$0-UUCk
Dateadd(wk,datediff(wk,0,getdate()),-1) s':fv[%
Dateadd(wk,datediff(wk,0,getdate()),6) joaf0
就是表示本周时间段. yl63VX8w}
下面的SQL的条件部分,就是查询时间段在本周范围内的: XAN{uD^3\%
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 4
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而在存储过程中 ~_vzss3-C
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) z:PH _N~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) PVBf'