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。 h'ik3mLH
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一、基础 XY0kd&N8
1、说明:创建数据库 3
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CREATE DATABASE database-name UrniJB]
2、说明:删除数据库 bGh&@&dHr
drop database dbname 'r'=%u$1C
3、说明:备份sql server &oL"AJU
--- 创建 备份数据的 device tqZ91QpW
USE master s/1r{;q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0%xk tf
--- 开始 备份 Nr4Fp`b8
BACKUP DATABASE pubs TO testBack Ff<cY%t
4、说明:创建新表 g4W$MI
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) k-$Acv(
根据已有的表创建新表: _z_YJ7A>
A:create table tab_new like tab_old (使用旧表创建新表) d`\SX(C
B:create table tab_new as select col1,col2... from tab_old definition only U$:^^Zt`B
5、说明:删除新表 [*%lm9 x
drop table tabname >N3X/8KL%
6、说明:增加一个列 EeaJUK]z9
Alter table tabname add column col type ,\`ruWWLb=
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。 )Rr6@o
7、说明:添加主键: Alter table tabname add primary key(col) ,Csdon
说明:删除主键: Alter table tabname drop primary key(col) ]t[%.^5#
8、说明:创建索引:create [unique] index idxname on tabname(col....) >WHajYO"
删除索引:drop index idxname v}>g* @
注:索引是不可更改的,想更改必须删除重新建。 Z<U,]iZB
9、说明:创建视图:create view viewname as select statement sbvP1|P8%
删除视图:drop view viewname (nqhX<T>
10、说明:几个简单的基本的sql语句 r$<!?Z
选择:select * from table1 where 范围 ~|u;z,\
插入:insert into table1(field1,field2) values(value1,value2) %6ckau1_;
删除:delete from table1 where 范围 }3
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更新:update table1 set field1=value1 where 范围 'O%*:'5k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! HoBx0N9\2
排序:select * from table1 order by field1,field2 [desc] rpk8
总数:select count as totalcount from table1 GTs,?t16/
求和:select sum(field1) as sumvalue from table1 tmGhJZ2j
平均:select avg(field1) as avgvalue from table1 x1=`Z@^
最大:select max(field1) as maxvalue from table1 U<6)CW1;
最小:select min(field1) as minvalue from table1 GzEw~JAs
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11、说明:几个高级查询运算词 %
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A: UNION 运算符 ;&lXgC^*
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 8YSvBy
B: EXCEPT 运算符 `!8\|/
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 1^IMoC7$#
C: INTERSECT 运算符 AyJl:aN^
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。 5a |[cR
注:使用运算词的几个查询结果行必须是一致的。 1dD%a91
12、说明:使用外连接 MpKXC
A、left outer join: 6@aH2+4+
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。 CI+)0=`<1B
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 x.t<@y~
B:right outer join: 8] LF{Obz[
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。 ~'*23]j
C:full outer join: CXUF=IE
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。 E2Sj IR}
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二、提升 d 6Y9D=O
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ['QhC( {
法一:select * into b from a where 1<>1 [,bJKz)a
法二:select top 0 * into b from a kwi$%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 'q}Ud10c
insert into b(a, b, c) select d,e,f from b; pyf'_
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) mR.j8pi
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =u0=)\0@r
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ZW M:Wj192
4、说明:子查询(表名1:a 表名2:b) r6j[C"@
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) ,WdSJ BK'a
5、说明:显示文章、提交人和最后回复时间 +s}!+I8P
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b :] Wn26z)
6、说明:外连接查询(表名1:a 表名2:b) "]^U(m>f
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ln<[CgV8
7、说明:在线视图查询(表名1:a ) /5%'q~
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7]@M
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 u%L6@M2
select * from table1 where time between time1 and time2 (,"%fc7<i
select a,b,c, from table1 where a not between 数值1 and 数值2 %2RXrH2&H
9、说明:in 的使用方法 mAH7;u<
select * from table1 where a [not] in ('值1','值2','值4','值6') 9f['TG,"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 x~'_;>]r_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [\F:NLjiUy
11、说明:四表联查问题: 4][VK/v+
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 ..... yS)k"XNb
12、说明:日程安排提前五分钟提醒 yO-2.2h
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (muJ-~CJk
13、说明:一条sql 语句搞定数据库分页 '"Cqq{*
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 ks$5$,^T2o
14、说明:前10条记录 <F`9;WX
select top 10 * form table1 where 范围 :WH{wm|
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.) H F*~bL
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6oKlr,.
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 iMry0z
(select a from tableA ) except (select a from tableB) except (select a from tableC) D~qi6@Ga
17、说明:随机取出10条数据 nUY)LnI
select top 10 * from tablename order by newid() ]V fp,"op
18、说明:随机选择记录 ym
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select newid() Bl)D/
19、说明:删除重复记录 6n:X
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ~m R^j
20、说明:列出数据库里所有的表名 w2$ L;q
select name from sysobjects where type='U' 2C0j.Ib
21、说明:列出表里的所有的 2SC'Z>A
select name from syscolumns where id=object_id('TableName') 0#c-qy
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。 1`II%mf[
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 depCqz@
显示结果: 9[t-W:3c7
type vender pcs :z?T/9,C
电脑 A 1
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电脑 A 1 MPp:EH
光盘 B 2 (*26aMp
光盘 A 2 **AJFc
手机 B 3 0o6r3xc;
手机 C 3 qoan<z7
23、说明:初始化表table1 `U?S 9m
TRUNCATE TABLE table1 &xj40IZ
24、说明:选择从10到15的记录 r?`nc6$0|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7|Qb}[s
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三、技巧 }zo-%#
1、1=1,1=2的使用,在SQL语句组合时用的较多 >iJxq6!
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?h7[^sxJ
如: 8}z PDs
if @strWhere !='' 'o_ RC{k2"
begin M/[9ZgDc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere xZAg
end ^')4RU
else E?0RR'
begin Nf~B 1vkp
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *nM.`7g*[
end ~9fTs4U
我们可以直接写成 Z,3CMWHg
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere G*v,-O
2、收缩数据库 _qit$#wK;
--重建索引 { F0"U=
DBCC REINDEX 6{Bvl[mhI
DBCC INDEXDEFRAG M~sP|Ha"+
--收缩数据和日志 RXPl~]k#i
DBCC SHRINKDB ;?o"{mbb
DBCC SHRINKFILE e?aSM
3、压缩数据库 sx9[#6~{Y
dbcc shrinkdatabase(dbname) yC}x6xG
4、转移数据库给新用户以已存在用户权限 g2lv4Tiq-
exec sp_change_users_login 'update_one','newname','oldname' )P/~{Ci:T&
go a0FU[*q
5、检查备份集 i;)r|L`V?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +w?1<Z
6、修复数据库 v|kL7t)}
ALTER DATABASE [dvbbs] SET SINGLE_USER bF@iO316H
GO ^w
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |?fc]dl1]
GO KueI*\ p
ALTER DATABASE [dvbbs] SET MULTI_USER m<9W#
GO ,g)9ZP.F
7、日志清除 w68VOymD/
SET NOCOUNT ON is-{U?-
DECLARE @LogicalFileName sysname, v2#qs*sW8
@MaxMinutes INT, Zfr?(y+3
@NewSize INT la!rg#)-X
USE tablename -- 要操作的数据库名 v CR\lR+
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 TwE&5F*
@MaxMinutes = 10, -- Limit on time allowed to wrap log. nYY' hjZ
@NewSize = 1 -- 你想设定的日志文件的大小(M) MU_
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-- Setup / initialize b~G|Bhxa
DECLARE @OriginalSize int RK]."m0c~#
SELECT @OriginalSize = size '$OLU[(Y
FROM sysfiles LD5E
WHERE name = @LogicalFileName RA62Z&W3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + XG6UV('
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )\0c2_w>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z Q9's
FROM sysfiles iQaF R@
WHERE name = @LogicalFileName f1VA61z{)
CREATE TABLE DummyTrans "_&HM4%!
(DummyColumn char (8000) not null) =7("xz%
DECLARE @Counter INT, A7:W0Gg
@StartTime DATETIME, hmd, g>J:<
@TruncLog VARCHAR(255) T\HP5&
SELECT @StartTime = GETDATE(), X"G3lG
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' y+[wlo&WC
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Yc'7F7.<6
EXEC (@TruncLog) [26([H
-- Wrap the log if necessary. YI?y_S
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 2|^bDg;W+u
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ].w$b)G
AND (@OriginalSize * 8 /1024) > @NewSize }oTac
BEGIN -- Outer loop. e.g$|C^$m
SELECT @Counter = 0 (3G]-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) P(r}<SM
BEGIN -- update 80M4~'3
INSERT DummyTrans VALUES ('Fill Log') KK*"s^L
DELETE DummyTrans ?+#E&F
SELECT @Counter = @Counter + 1 ?3i-wpzMp
END M*c`@\
EXEC (@TruncLog) sXSZ#@u,WN
END .!t'&eV
SELECT 'Final Size of ' + db_name() + ' LOG is ' + k4-C*Gx$h
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ZjJEjw
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T+/Gz'
FROM sysfiles Wm ?RB0
WHERE name = @LogicalFileName BPKeG0F7
DROP TABLE DummyTrans ex2*oqAdX
SET NOCOUNT OFF 5G=CvGu
8、说明:更改某个表 FCmS3KIa,
exec sp_changeobjectowner 'tablename','dbo' !$5U\"M
9、存储更改全部表 3' 6>zp
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch #/1,Cv yj
@OldOwner as NVARCHAR(128), gasl%&
@NewOwner as NVARCHAR(128) |5,q54d(K
AS ,G,T&W
DECLARE @Name as NVARCHAR(128) CLD*\)QD\
DECLARE @Owner as NVARCHAR(128) HgX4RSU
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR NC2PW+(
select 'Name' = name, `ml;#n,*
'Owner' = user_name(uid) O@_)]z?jUc
from sysobjects I|$_[Sw
where user_name(uid)=@OldOwner [H)p#x
order by name \9BIRY`
OPEN curObject A!
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FETCH NEXT FROM curObject INTO @Name, @Owner }g _#.>D+
WHILE(@@FETCH_STATUS=0) B)"WG7W E
BEGIN ~c3CyOab
if @Owner=@OldOwner ZA ii"F
begin Kc\0-3 Z
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ziy~~J
exec sp_changeobjectowner @OwnerName, @NewOwner W"WvkW>-
end )5X7|*LP
-- select @name,@NewOwner,@OldOwner ?z60b=f8
FETCH NEXT FROM curObject INTO @Name, @Owner BiHBu8<
END _" F(w"|
close curObject 4S.%y7d\
deallocate curObject NzRL(A6V
GO =N
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10、SQL SERVER中直接循环写入数据 I)O-i_}L&K
declare @i int YKUs>tQ!
set @i=1 ]0dp^%
while @i<30 :/Nz' n
begin ou-5iH?
insert into test (userid) values(@i) GYv2^IB:
set @i=@i+1 !=0N38wA
end Y6fU;
小记存储过程中经常用到的本周,本月,本年函数 JX/rAnc@
Dateadd(wk,datediff(wk,0,getdate()),-1) !H,R$3~
Dateadd(wk,datediff(wk,0,getdate()),6) e$tKKcj0T
Dateadd(mm,datediff(mm,0,getdate()),0) Fu m1w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^ yu^Du
Dateadd(yy,datediff(yy,0,getdate()),0) .)u,sYZA|
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |)IN20
上面的SQL代码只是一个时间段 T.W/S0#j3
Dateadd(wk,datediff(wk,0,getdate()),-1) OY`G _=6!N
Dateadd(wk,datediff(wk,0,getdate()),6) K#";!
就是表示本周时间段. 88)0Xi|]KP
下面的SQL的条件部分,就是查询时间段在本周范围内的: WohK,<Or
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )CXJRo`j0
而在存储过程中 |g4!Yd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m.EWYO0XQ