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。 O%h
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一、基础 {*P7)
1、说明:创建数据库 j`-y"6)
CREATE DATABASE database-name (Y@|h%1W
2、说明:删除数据库 u KdX4
drop database dbname T{J`t*Ym
3、说明:备份sql server Fm+)mmJP
--- 创建 备份数据的 device 'C4Ll2
USE master }[R@HmN
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' t;PnjCD<`
--- 开始 备份 o_+Qer=O6
BACKUP DATABASE pubs TO testBack Vy"^]5
4、说明:创建新表 !(AFT!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) x/q$RcDOm
根据已有的表创建新表: jc.Uh9Kc
A:create table tab_new like tab_old (使用旧表创建新表) dM;WG;8e
B:create table tab_new as select col1,col2... from tab_old definition only 1+ARV&bc
5、说明:删除新表 Dve5m=
drop table tabname I6Q_A
6、说明:增加一个列 745V!#3!M
Alter table tabname add column col type RloPP
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。 03jBN2[!
7、说明:添加主键: Alter table tabname add primary key(col) 5|={1Lp24g
说明:删除主键: Alter table tabname drop primary key(col) V\8
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8、说明:创建索引:create [unique] index idxname on tabname(col....) %cif0Td
删除索引:drop index idxname &!aLOx*3`
注:索引是不可更改的,想更改必须删除重新建。 0r&9AnnWu+
9、说明:创建视图:create view viewname as select statement HbVV]y
删除视图:drop view viewname B{i;+[ase
10、说明:几个简单的基本的sql语句 uWT&`m_(2
选择:select * from table1 where 范围 49kia!FR
插入:insert into table1(field1,field2) values(value1,value2) `r bqYU0
删除:delete from table1 where 范围 6_
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更新:update table1 set field1=value1 where 范围 v-aq".XQ
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] E|#R0n*
总数:select count as totalcount from table1 j`pR;XL1[
求和:select sum(field1) as sumvalue from table1 a;6\T*iJ!
平均:select avg(field1) as avgvalue from table1 {Ag}P0%'
最大:select max(field1) as maxvalue from table1 P`v~L;f
最小:select min(field1) as minvalue from table1 -L<Pm(v&
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11、说明:几个高级查询运算词 l[0P*(I,
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A: UNION 运算符 vrDRSc6_
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。 6242qb
B: EXCEPT 运算符 !`U<RlK7
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。 RN3D:b+
C: INTERSECT 运算符 V2* |j8|
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。 Q 8E~hgO
注:使用运算词的几个查询结果行必须是一致的。 }iloX#
12、说明:使用外连接 *}&aK}h}I
A、left outer join: (6^k;j
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。 ZKL%rp_
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 [\F,\
B:right outer join: Ox'.sq4
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!ICno6[e
C:full outer join: . +?lID
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。 ;MI<J>s
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二、提升 ZEJadR
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) D/`E!6Fk=
法一:select * into b from a where 1<>1 Kn\(Xd.>
法二:select top 0 * into b from a za/#R_%p
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B)`X7uG
insert into b(a, b, c) select d,e,f from b; rl7Y=*Dv
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) ]vFmY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }w8AnaC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. aH"c0A
4、说明:子查询(表名1:a 表名2:b) .AW*7Pp`f
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) >u2#<k]1&
5、说明:显示文章、提交人和最后回复时间 @S92D6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b WcG&W>
6、说明:外连接查询(表名1:a 表名2:b) Zi)8KO[/0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c T480w6-@
7、说明:在线视图查询(表名1:a ) PyF4uCn"H
select * from (SELECT a,b,c FROM a) T where t.a > 1; }O{"qs#)
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 PSE|4{'
select * from table1 where time between time1 and time2 *xC '
select a,b,c, from table1 where a not between 数值1 and 数值2 "c*|vE
9、说明:in 的使用方法 h;M2ylOu.
select * from table1 where a [not] in ('值1','值2','值4','值6') O~xmz!?=
10、说明:两张关联表,删除主表中已经在副表中没有的信息 \LXC269
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i%
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11、说明:四表联查问题: I\23as0q
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 ..... ufPQ~,.
12、说明:日程安排提前五分钟提醒 TZ2f-KI
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 B6oAW ,3
13、说明:一条sql 语句搞定数据库分页 OK}"|:hrd
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 F#wa)XH
14、说明:前10条记录 z+I-3v
select top 10 * form table1 where 范围 5al{[mi
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.) =SnR9In
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &O)mPnx`
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 .D`#a
(select a from tableA ) except (select a from tableB) except (select a from tableC) C%>7mz-v5
17、说明:随机取出10条数据 M(jH"u&f
select top 10 * from tablename order by newid() 4UkLvL1x
18、说明:随机选择记录 /B7
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select newid() dp+Y?ufr
19、说明:删除重复记录 x6tY _lzJ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !W7ekPnK
20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' Hd`RR3J
21、说明:列出表里的所有的 eX@q'Zi
select name from syscolumns where id=object_id('TableName') Uo
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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。 K_}acU
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 LsV"h<
显示结果: |_*1/Wz@
type vender pcs Akf9nT
电脑 A 1 RI;RE/Z
电脑 A 1 ,Pm/ci(s
光盘 B 2 }tPl?P'`
光盘 A 2 ZP<X#]$qb
手机 B 3 CcTJCuOS
手机 C 3 4+ gA/<
23、说明:初始化表table1 Wg1WY}zG
TRUNCATE TABLE table1 )^+$5OR\c
24、说明:选择从10到15的记录 0oMMJ6"i
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc TW0^wSm
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三、技巧 Gov{jksr
1、1=1,1=2的使用,在SQL语句组合时用的较多 B!v1gh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \m!."~%
如: 6dUP's_
if @strWhere !='' HvTQycG
begin d6VKUAk'7>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |T%/d#b~
end ~k3r$e@
else _HQa3wj
begin KWo)}m*6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' HApP*1J^c
end w[ngkLEA
我们可以直接写成 5;l_-0=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @C2<AmY9q*
2、收缩数据库 E
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--重建索引 f@mM&e=f
DBCC REINDEX {UN z UaE
DBCC INDEXDEFRAG b4wJnmC8
--收缩数据和日志 7>LhXC
DBCC SHRINKDB J:(l&
DBCC SHRINKFILE W8^gPW*c5
3、压缩数据库 g:g>;"B
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dbcc shrinkdatabase(dbname) I"1\R8
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4、转移数据库给新用户以已存在用户权限 q.7CPm+
exec sp_change_users_login 'update_one','newname','oldname' ^ytd~iK8
go $j/F7.S
5、检查备份集 V1G]LM
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' !QovpO">z
6、修复数据库 )94R\f
ALTER DATABASE [dvbbs] SET SINGLE_USER r%m2$vx#
GO 2i)y'+s
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1"k@O)?JP
GO :Us-^zVr
ALTER DATABASE [dvbbs] SET MULTI_USER x@~V975Y
GO [~3p+
7、日志清除 *)1,W+A5L
SET NOCOUNT ON {IVqV6:
DECLARE @LogicalFileName sysname, m[pzu2R
@MaxMinutes INT, WJ*DWyd''
@NewSize INT `uj`ixcR
USE tablename -- 要操作的数据库名 =bzTfki
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \Mi< ROp5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N?XN$hwdZ
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,]MX&]
-- Setup / initialize mR^D55k
DECLARE @OriginalSize int k#.co~kS
SELECT @OriginalSize = size @&+
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FROM sysfiles QEPmuG
WHERE name = @LogicalFileName C*9m `xh
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3,?y !
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + saV `-#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' /dqKFxB1
FROM sysfiles |F<aw?%
WHERE name = @LogicalFileName ec=C7M
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CREATE TABLE DummyTrans I2dt#
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, 'K1w.hC<
@StartTime DATETIME, =aCv
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@TruncLog VARCHAR(255) aE"t['
SELECT @StartTime = GETDATE(), Wac8x%J
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -=RXhE_{
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 2g$Wv :E3
EXEC (@TruncLog) K6X1a7
-- Wrap the log if necessary. gLH(Wr~(a
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired NJp;t[v.^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) FueJe/~t
AND (@OriginalSize * 8 /1024) > @NewSize tL~|/C)d R
BEGIN -- Outer loop. D7%89qt
SELECT @Counter = 0 <3qbgn>}b
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^\!p;R
BEGIN -- update e:l 6;
INSERT DummyTrans VALUES ('Fill Log') R3~&|>7/T
DELETE DummyTrans (F)zj<{f
SELECT @Counter = @Counter + 1 ivm.ng[
END A9#2.5
EXEC (@TruncLog) N%-nxbI\
END [Y*UCFhI0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ubLLhf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + .28*vkH%C=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' QWoEo
FROM sysfiles k"Is.[I?^
WHERE name = @LogicalFileName i <bs{Cu_S
DROP TABLE DummyTrans h^s}8y
SET NOCOUNT OFF _,}Ye,(^=
8、说明:更改某个表 _i
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exec sp_changeobjectowner 'tablename','dbo' j\a?n4g -
9、存储更改全部表 ZjcJYtD
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch S("bN{7nE
@OldOwner as NVARCHAR(128), q=bXHtU
@NewOwner as NVARCHAR(128) *8N~Zmz
AS
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DECLARE @Name as NVARCHAR(128) ,wV2ZEW}e
DECLARE @Owner as NVARCHAR(128) %vksN$^
DECLARE @OwnerName as NVARCHAR(128) j% nd
DECLARE curObject CURSOR FOR ~i
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select 'Name' = name, ^K"`k43{
'Owner' = user_name(uid) ]?r8^L yZ4
from sysobjects i8{jMe!Sa
where user_name(uid)=@OldOwner I#0.72:[
order by name ofSOy1
OPEN curObject 6f?DW-)jp/
FETCH NEXT FROM curObject INTO @Name, @Owner exhF5,AW|K
WHILE(@@FETCH_STATUS=0) Qhr:d`@^]
BEGIN 4k#6)e
if @Owner=@OldOwner zumRbrz
begin M3Z yf
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6k[u0b`
exec sp_changeobjectowner @OwnerName, @NewOwner NOx|
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end TwH(47|?Nt
-- select @name,@NewOwner,@OldOwner ,9rT|:N
FETCH NEXT FROM curObject INTO @Name, @Owner 1/i|
END K.%E=^~q
close curObject :J"e{|g',
deallocate curObject OLi;/(g
GO >}9TdP/oT
10、SQL SERVER中直接循环写入数据 uODsXi{z
declare @i int \DHCf4,
set @i=1 =nsY[ s<
while @i<30 <7p2OPD
begin \yy!?UlaI
insert into test (userid) values(@i) 1w5nBVC*$V
set @i=@i+1 Ip4~qGJ
end LP\ Qwj{
小记存储过程中经常用到的本周,本月,本年函数 @6gz)
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Dateadd(wk,datediff(wk,0,getdate()),-1) o _-t/
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Dateadd(wk,datediff(wk,0,getdate()),6) 2vXMrh\
Dateadd(mm,datediff(mm,0,getdate()),0) 3.jwOFH$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) LDNpEX~
Dateadd(yy,datediff(yy,0,getdate()),0) aql*@8
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) l}wBthwCc
上面的SQL代码只是一个时间段 e7;]+pN]J
Dateadd(wk,datediff(wk,0,getdate()),-1) sJD"u4#y
Dateadd(wk,datediff(wk,0,getdate()),6) giTlXz3D9
就是表示本周时间段. ABSeX
下面的SQL的条件部分,就是查询时间段在本周范围内的: A=])pYE1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8RK\B%UW
而在存储过程中 QdRMp
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) JDP#tA3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) JWBWa-