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。 eGg6wd
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一、基础 Q:Pp'[ RK
1、说明:创建数据库 *yw!Y{e!9
CREATE DATABASE database-name U^GVz%\
2、说明:删除数据库 z8'zH>
drop database dbname q78OP}
3、说明:备份sql server LTzdg >\oJ
--- 创建 备份数据的 device @v@F%JCZ
USE master _eq$C=3Ta
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #BcUE?K*N
--- 开始 备份 41d+z>a]
BACKUP DATABASE pubs TO testBack <z2.A/L
4、说明:创建新表 2[3t7 C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QtG6v<A
根据已有的表创建新表: ps:`rVQ7
A:create table tab_new like tab_old (使用旧表创建新表) 13Z,;YW
B:create table tab_new as select col1,col2... from tab_old definition only HyWR&0J
5、说明:删除新表 '" %0UflJS
drop table tabname f 42F@M(:
6、说明:增加一个列 ~7KH/%Z-
Alter table tabname add column col type wG7>2*(
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 @ :PMb Ub
7、说明:添加主键: Alter table tabname add primary key(col) :x[()J~N
说明:删除主键: Alter table tabname drop primary key(col) Ri`6X_xU
8、说明:创建索引:create [unique] index idxname on tabname(col....) Mb[4_Dc
删除索引:drop index idxname @$^4Av-
注:索引是不可更改的,想更改必须删除重新建。 Z]G#:
9、说明:创建视图:create view viewname as select statement -
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删除视图:drop view viewname hZ>m:es
10、说明:几个简单的基本的sql语句 :ChXzZ
选择:select * from table1 where 范围 a}f/<-L
插入:insert into table1(field1,field2) values(value1,value2) 7?uDh'utt
删除:delete from table1 where 范围 ]g ;+7
更新:update table1 set field1=value1 where 范围 b(R.&X
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ko[d axUB
排序:select * from table1 order by field1,field2 [desc] =hb)e}l
总数:select count as totalcount from table1 !',%kvJI
求和:select sum(field1) as sumvalue from table1 b/m.VL
平均:select avg(field1) as avgvalue from table1 _+aR|AEC
最大:select max(field1) as maxvalue from table1 '{.4~:
最小:select min(field1) as minvalue from table1 4.wrY6+V
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11、说明:几个高级查询运算词 56c[$ q
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A: UNION 运算符 O.QR1
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。 `W@jo~y<
B: EXCEPT 运算符 L-}Uj^yF
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。 Rzsu 7w
C: INTERSECT 运算符 j0~c2
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。 \6/Gy!0h-
注:使用运算词的几个查询结果行必须是一致的。 |4pl}:g/Z
12、说明:使用外连接 2bw), W
A、left outer join: nj;3U^
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。 Z:AB(c
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 eHs38X
B:right outer join: `W+-0F@Y?@
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。 "62g!e}!c
C:full outer join: '&,p>aM
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。
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二、提升 3w |5%`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) F7b%
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法一:select * into b from a where 1<>1 H{N},B
法二:select top 0 * into b from a '-N5F
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) wL:7G
insert into b(a, b, c) select d,e,f from b; z?Z"*z
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) T*#M'H7LSQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )i:*r8*~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Bnk<e
4、说明:子查询(表名1:a 表名2:b) T_UJ?W
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) R6Md_t\
5、说明:显示文章、提交人和最后回复时间 Q=DMfJ"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6m]?*k1HC
6、说明:外连接查询(表名1:a 表名2:b) vuY X0&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c D~i 5E9s5
7、说明:在线视图查询(表名1:a ) EHhc2^e
select * from (SELECT a,b,c FROM a) T where t.a > 1; rf]z5;
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 xgkCN$zQ`
select * from table1 where time between time1 and time2 y!x[N!a
select a,b,c, from table1 where a not between 数值1 and 数值2 $*N(feAs
9、说明:in 的使用方法 .nVY" C&
select * from table1 where a [not] in ('值1','值2','值4','值6') 1c]{rO=taN
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?#&[1.= u
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -
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11、说明:四表联查问题: pYAKA1F
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... eE
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12、说明:日程安排提前五分钟提醒 [ypE[
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {2T u_2>
13、说明:一条sql 语句搞定数据库分页 o(?9vU
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ~J~R.r/
14、说明:前10条记录 AsuugcN*
select top 10 * form table1 where 范围 WwWOic2
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) MxX)&327
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [9 :9<#?o^
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 II _CT=
(select a from tableA ) except (select a from tableB) except (select a from tableC) F,VWi$Po\N
17、说明:随机取出10条数据 Uea2WJpX
select top 10 * from tablename order by newid() H<ovIMd
18、说明:随机选择记录 [hH>BEtm
select newid() 2g5 4<G*e
19、说明:删除重复记录 37?X@@Z=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <v_Wh@m
20、说明:列出数据库里所有的表名 Lh-Y5(c
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select name from sysobjects where type='U' %q eNC\6N
21、说明:列出表里的所有的 #"TYk@whWf
select name from syscolumns where id=object_id('TableName') Wql=PqF
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。 B+R|fQ
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 l'2vo=IQ
显示结果: 2{l|<'
type vender pcs QALr
电脑 A 1 jJvd!,=)
电脑 A 1 I(&N2L$-
光盘 B 2 $Fc}K+
光盘 A 2 .)%,R
手机 B 3 Uh1UZ
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手机 C 3 KkzG#'I1
23、说明:初始化表table1 *'M+oi
TRUNCATE TABLE table1 z$g__q-
24、说明:选择从10到15的记录 fn7?g
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Wq 1OYZ,
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三、技巧 fU%Mz\t
1、1=1,1=2的使用,在SQL语句组合时用的较多 <pG 4g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, V}2[chbl
如: e iH&<AH
if @strWhere !='' AhjCRYk+
begin 0/z$W.!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #\xy,C'Y
end cL#zE
else UF89gG4
begin e&[~}f?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' T(cpU,Q
end Aq'~'hS`1
我们可以直接写成 6y?uH;SL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^
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2、收缩数据库 R Eo{E
--重建索引 &g*1 If
DBCC REINDEX jzi^OI7
DBCC INDEXDEFRAG r`+G9sj3U
--收缩数据和日志 mmNn,>AO!
DBCC SHRINKDB p>T
DBCC SHRINKFILE fL'Ci;.;+
3、压缩数据库 hHOx ]
dbcc shrinkdatabase(dbname) mv$gL
4、转移数据库给新用户以已存在用户权限 Fy6Lz.baB
exec sp_change_users_login 'update_one','newname','oldname' ,^v_gc
go r=RiuxxTq
5、检查备份集
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' H~ >\HV*
6、修复数据库 =|^R<#%/
ALTER DATABASE [dvbbs] SET SINGLE_USER :F"NF
GO nU2w\(3|
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <]`|HJoy
GO Q+U" %
ALTER DATABASE [dvbbs] SET MULTI_USER RWJyd=
GO Mt~2&$>
7、日志清除 f{(D+7e}
SET NOCOUNT ON ue!4By8T
DECLARE @LogicalFileName sysname, zx?|5=+!
@MaxMinutes INT, $ 93j;
@NewSize INT hb)83mH}
USE tablename -- 要操作的数据库名 _.W;hf`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `w"ooK
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 2ryg3%+O
@NewSize = 1 -- 你想设定的日志文件的大小(M) T{'oR .g,
-- Setup / initialize mMK 93Ng"&
DECLARE @OriginalSize int 1n>AN.nI
SELECT @OriginalSize = size s|:j~>53
FROM sysfiles GgvMd~
WHERE name = @LogicalFileName )@.0ai
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]==S?_.B3n
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Y)AHM0;g
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +xYg<AFS
FROM sysfiles NV2$ >D
WHERE name = @LogicalFileName j4(f1
CREATE TABLE DummyTrans {^R"V ,)
(DummyColumn char (8000) not null) A_.}-dzF
DECLARE @Counter INT, =u5( zaBe
@StartTime DATETIME, TSRl@QVy
@TruncLog VARCHAR(255) &w^:nVgl
SELECT @StartTime = GETDATE(), vH"^a/95|
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' z&.F YGq}
DBCC SHRINKFILE (@LogicalFileName, @NewSize) AnBD~h h
EXEC (@TruncLog) @@6c{r^P
-- Wrap the log if necessary. bW^{I,b<F
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired lygv#s-T
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) r{Z4ifSl(
AND (@OriginalSize * 8 /1024) > @NewSize *i,A(f'e4X
BEGIN -- Outer loop. . H8 6f !=
SELECT @Counter = 0 qI2&a$Zb$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &?APY9\.
BEGIN -- update 9Om3<der
INSERT DummyTrans VALUES ('Fill Log') eqU y>
DELETE DummyTrans -9q3]nmT(
SELECT @Counter = @Counter + 1 gt(!I^LHYc
END mqQC`Aqx:
EXEC (@TruncLog) .JWN\\
END {jEEAH)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6dqI{T-i?
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /t _QA
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #nS crs@
FROM sysfiles }Y3*X:i7
WHERE name = @LogicalFileName (U|WP%IM'
DROP TABLE DummyTrans TmLfH
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SET NOCOUNT OFF E
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8、说明:更改某个表 @`rC2-V
exec sp_changeobjectowner 'tablename','dbo' <*HsJwr)u
9、存储更改全部表 eeOG(@@o(
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "'I|#dKoG
@OldOwner as NVARCHAR(128), "1-z'TV=
@NewOwner as NVARCHAR(128) O
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AS Vx=tP.BO]
DECLARE @Name as NVARCHAR(128) /9
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DECLARE @Owner as NVARCHAR(128) 81S0: =
DECLARE @OwnerName as NVARCHAR(128) j
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DECLARE curObject CURSOR FOR Ak@y"!wnM
select 'Name' = name, 0@}:`OynX
'Owner' = user_name(uid) ,o6,(jJU
from sysobjects Ev1gzHd!i
where user_name(uid)=@OldOwner cIXqnb
order by name D4U<Rn6N_5
OPEN curObject f(*iagEy
FETCH NEXT FROM curObject INTO @Name, @Owner 1<pb=H
WHILE(@@FETCH_STATUS=0) X->` ~-aj
BEGIN g"X!&$&
if @Owner=@OldOwner 0
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begin md/NMC
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) jFwJ1W;?-
exec sp_changeobjectowner @OwnerName, @NewOwner =nG>aAG
end mC!^`y)
-- select @name,@NewOwner,@OldOwner t^g+nguz
FETCH NEXT FROM curObject INTO @Name, @Owner %[k"A
END :2AlvjvjZ
close curObject \&^U9=uq
deallocate curObject G5!!^p~
GO @6{F4
10、SQL SERVER中直接循环写入数据 m/ngPeZ
declare @i int HXQ
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set @i=1 q$jwH]
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while @i<30 ;Bne=vjQp
begin \NQ[w7
insert into test (userid) values(@i) [&:dPd1_
set @i=@i+1 F|?}r3{aJ
end .}iRe}=
小记存储过程中经常用到的本周,本月,本年函数 ~R~MC(5N[
Dateadd(wk,datediff(wk,0,getdate()),-1) )Xice=x9
Dateadd(wk,datediff(wk,0,getdate()),6) QTjnXg?Ri
Dateadd(mm,datediff(mm,0,getdate()),0) 9K=K,6
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %H=^U8WB
Dateadd(yy,datediff(yy,0,getdate()),0) agnEYdM_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k~=P0";
上面的SQL代码只是一个时间段 cs)R8vuB)z
Dateadd(wk,datediff(wk,0,getdate()),-1) DfVSG1g
Dateadd(wk,datediff(wk,0,getdate()),6) ->J5|c#
就是表示本周时间段. Ba9"IXKH
下面的SQL的条件部分,就是查询时间段在本周范围内的: OwLJS5r@<-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (O'O#AD
而在存储过程中 ){4$oXQ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) =Kt!+^\")
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @Qd5a(5W M