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。 B!0[LlF+
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一、基础 p[Es4S}N
1、说明:创建数据库 r|+Zni]
CREATE DATABASE database-name IkkrnG8
2、说明:删除数据库 H b.oKo$T
drop database dbname bmLNR
3、说明:备份sql server A|^?.uIM
--- 创建 备份数据的 device u CXd%
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USE master :>=,sLfJ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' NNX/2
--- 开始 备份 _>.%X45xi
BACKUP DATABASE pubs TO testBack cQjJ9o7
4、说明:创建新表 23PSv8;EM
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {#MViBhd%
根据已有的表创建新表: xUYSD
A:create table tab_new like tab_old (使用旧表创建新表) 0#G"{M
B:create table tab_new as select col1,col2... from tab_old definition only )%6v~,'3Y
5、说明:删除新表 |j;`;"+B
drop table tabname 6tM{cK%v1
6、说明:增加一个列 -kO=pYP*O
Alter table tabname add column col type ocvBKsfhE`
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 D c^d$gh
7、说明:添加主键: Alter table tabname add primary key(col) h!.(7qdd
说明:删除主键: Alter table tabname drop primary key(col) {|cA[#j#
8、说明:创建索引:create [unique] index idxname on tabname(col....) Tn|reXc0e
删除索引:drop index idxname 0)Z7U$
注:索引是不可更改的,想更改必须删除重新建。 o?>)CAo
9、说明:创建视图:create view viewname as select statement N{'k
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删除视图:drop view viewname zI(Pti
10、说明:几个简单的基本的sql语句 Z'E@sc 9
选择:select * from table1 where 范围 9iUw7-)
插入:insert into table1(field1,field2) values(value1,value2) Uvp?HZ\Z
删除:delete from table1 where 范围 `&o|=
更新:update table1 set field1=value1 where 范围 GC~::m~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! h W-[omr0
排序:select * from table1 order by field1,field2 [desc] P VPwYmte
总数:select count as totalcount from table1 2
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求和:select sum(field1) as sumvalue from table1 F~:5/-zs
平均:select avg(field1) as avgvalue from table1 b$BUo8O}
最大:select max(field1) as maxvalue from table1 z9gZ/d
最小:select min(field1) as minvalue from table1 *\>&
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11、说明:几个高级查询运算词 C9fJLCufC
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A: UNION 运算符 975KRnj
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。 rpvm].4
B: EXCEPT 运算符 L:31toGK
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。 _T1e##Sq,
C: INTERSECT 运算符 y
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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。 :sf;Fq
注:使用运算词的几个查询结果行必须是一致的。 ixp %aRRP
12、说明:使用外连接 ;J4_8N-
A、left outer join: `f(!i mN
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。 *]rV,\z:
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 o,d:{tt
B:right outer join: hX^XtIC=
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。 W uQdz&s>
C:full outer join: *Q)+Y&qn
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。 \(u P{,ML
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二、提升 S+He
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) SXhJz=h
法一:select * into b from a where 1<>1 vK$W)(Z
法二:select top 0 * into b from a dCinbAQ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d00r&Mc
insert into b(a, b, c) select d,e,f from b; 9O|m#&wa]
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) @?t) UE
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 iaMZ37
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. g3y44GCV
4、说明:子查询(表名1:a 表名2:b) KMZ% 1=a
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) S_)va#b#
5、说明:显示文章、提交人和最后回复时间 Dx8^V%b
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6K,AQ.=V2
6、说明:外连接查询(表名1:a 表名2:b) )t|M)z J
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ].$N@tC
7、说明:在线视图查询(表名1:a ) MQI6e".
select * from (SELECT a,b,c FROM a) T where t.a > 1; //`X+[bMG
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 ~ >6(@~6
select * from table1 where time between time1 and time2 !#'*@a
select a,b,c, from table1 where a not between 数值1 and 数值2 \X(.%5xC
9、说明:in 的使用方法 $ (GXlhA
select * from table1 where a [not] in ('值1','值2','值4','值6') 1(-)$m8}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ZqSczS7uf
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i6[Hu8
11、说明:四表联查问题: ~; MRQE
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 ..... /u?^s "C/
12、说明:日程安排提前五分钟提醒 bkV_ ^8
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 \KTX{qI"f
13、说明:一条sql 语句搞定数据库分页 x]F:~(P
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 qLcs)&}/A
14、说明:前10条记录 &n['#7 <(!
select top 10 * form table1 where 范围 1%>/%eyn5
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.) 7r:!HmRl
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) XXO
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 $[H3O(B0*
(select a from tableA ) except (select a from tableB) except (select a from tableC) D&.+Dx^G
17、说明:随机取出10条数据 LnLuWr<;}
select top 10 * from tablename order by newid() o_{-X 1w
18、说明:随机选择记录 ]@_*O$
select newid() /CH*5w)1
19、说明:删除重复记录 6z~6o0s~
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L9@nx7D
20、说明:列出数据库里所有的表名 B
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select name from sysobjects where type='U' ?xIwQd0
21、说明:列出表里的所有的 `Os@/S
select name from syscolumns where id=object_id('TableName') ) !3sB{H
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。 F6yMk%
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 h/5.>[VwDh
显示结果: f`T#=6C4|
type vender pcs +dlN^P647
电脑 A 1 |'.\}xt7
电脑 A 1 BjSLbw-C
光盘 B 2 )[>{
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光盘 A 2 PyK)ks!6
手机 B 3 m$ "B=b2
手机 C 3 \:8
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23、说明:初始化表table1 m#ID%[hg$
TRUNCATE TABLE table1 $vx]\`
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24、说明:选择从10到15的记录 L~>pSP^a
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc wgY:W:y'N
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三、技巧 6,| !zaeS
1、1=1,1=2的使用,在SQL语句组合时用的较多 Z!DGCw
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ).5$c0`U&
如: 54v}iG
if @strWhere !='' z]K:Amp;Z
begin |BN^5mqP6
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere p4[cPt ~C
end Kx7s
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else DYx3NDX7
begin it \3-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' oUoDj'JN{
end yHe%e1
我们可以直接写成 HZKqGkE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ogtl
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2、收缩数据库 4;=+qb
--重建索引 ]sB-}n)
DBCC REINDEX |bDUekjR
DBCC INDEXDEFRAG E{*d`n
--收缩数据和日志 3,t3\`=
DBCC SHRINKDB h_n`E7&bG
DBCC SHRINKFILE jYI\.bc
3、压缩数据库 .]24V!J(1w
dbcc shrinkdatabase(dbname) q-}qrg
4、转移数据库给新用户以已存在用户权限 JYc;6p$<i
exec sp_change_users_login 'update_one','newname','oldname' $9bLD
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go c <Fr^8
5、检查备份集 /?VwoSgV^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' g[4pG`z
6、修复数据库 _c,c;
ALTER DATABASE [dvbbs] SET SINGLE_USER ^zn&"@
GO J#ujI e
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;LD!eWSK,
GO ir!/{IQx
ALTER DATABASE [dvbbs] SET MULTI_USER p?PK8GL
GO vnc-W3N
7、日志清除 it77x3Mm
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SET NOCOUNT ON c&X2k\
DECLARE @LogicalFileName sysname, mQUI9
@MaxMinutes INT, Xs}.7
@NewSize INT grrM[Y7#~b
USE tablename -- 要操作的数据库名 UU'0WIbY6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 a]\l:r
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4h~CDy%_
@NewSize = 1 -- 你想设定的日志文件的大小(M) ip8%9fG\>
-- Setup / initialize fRh}n ^X
DECLARE @OriginalSize int #p$iWY>e~
SELECT @OriginalSize = size y rH@:D/
FROM sysfiles lu vrv m
WHERE name = @LogicalFileName (X zy~l<
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <x-7MU&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /0 CS2mLC
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *!NxtB!LC
FROM sysfiles TMJq-u51
WHERE name = @LogicalFileName W-D{cU
CREATE TABLE DummyTrans }l"pxp1K
(DummyColumn char (8000) not null) #|8Ia:=s
DECLARE @Counter INT, >UNx<=ry
@StartTime DATETIME, z*k(` '
@TruncLog VARCHAR(255) h>k[
SELECT @StartTime = GETDATE(), <
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Nux
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4]G J+a
EXEC (@TruncLog) FJQ=611@
-- Wrap the log if necessary. Uhs/F:E[A
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 4Dy|YH$>S
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *\gYs{,
AND (@OriginalSize * 8 /1024) > @NewSize +cWo^ d.
BEGIN -- Outer loop. g|TWoRx:
SELECT @Counter = 0 0#Ae<
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) QlE]OAdB42
BEGIN -- update O#MaZ.=
INSERT DummyTrans VALUES ('Fill Log') N1iP!m9Q
DELETE DummyTrans )5Wt(p:T6_
SELECT @Counter = @Counter + 1 &$yxAqdab
END +9exap27
EXEC (@TruncLog) /#}o19(-d
END ;x.5_Xw{.
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3FY87R
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + j[CXIz?c
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <c3Te$.
FROM sysfiles oZ5 ,y+L4
WHERE name = @LogicalFileName L9{y1'')
DROP TABLE DummyTrans Y[!s:3\f
SET NOCOUNT OFF CFXr=.yz
8、说明:更改某个表 4v.{C"M
exec sp_changeobjectowner 'tablename','dbo' jZr"d*Y
9、存储更改全部表 ]$~\GE^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch I
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@OldOwner as NVARCHAR(128), dOX"7kZ
@NewOwner as NVARCHAR(128) ?k`UQi]Q
AS 'D'H)J
DECLARE @Name as NVARCHAR(128) `l2h65\
DECLARE @Owner as NVARCHAR(128) 18,;2Sr44
DECLARE @OwnerName as NVARCHAR(128) b|pp}il
DECLARE curObject CURSOR FOR u.ej<Lo
select 'Name' = name, !mH
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'Owner' = user_name(uid) uN&UYJ'B
from sysobjects U0=: `G2l
where user_name(uid)=@OldOwner qr4.s$VGs*
order by name 1R,SA:L$
OPEN curObject IFsh"i
FETCH NEXT FROM curObject INTO @Name, @Owner ;F|8#! (
WHILE(@@FETCH_STATUS=0) nvB<pSm
BEGIN s+t[{i4|
if @Owner=@OldOwner T*z*x=<5
begin dWTc3@xd
set @OwnerName = @OldOwner + '.' + rtrim(@Name) E(F?o.b
exec sp_changeobjectowner @OwnerName, @NewOwner jP#I](\eG
end 1>=%TIO)
-- select @name,@NewOwner,@OldOwner m*|G2
FETCH NEXT FROM curObject INTO @Name, @Owner hx! :F"#
END .cm9&&"Z
close curObject o-<XR9,N*
deallocate curObject ~6=aoF5"3?
GO '>cZ7:
10、SQL SERVER中直接循环写入数据 068DC_
declare @i int :.=#U
set @i=1 XTJA"y
while @i<30 "m>BE
begin 4Ss*h,Y
insert into test (userid) values(@i) `m}G{ jfk
set @i=@i+1 Y0yu,
end ~p?D[]h
小记存储过程中经常用到的本周,本月,本年函数 3 S .2
Dateadd(wk,datediff(wk,0,getdate()),-1) @ 3rJ $6W
Dateadd(wk,datediff(wk,0,getdate()),6) 3"Zc|Ck <?
Dateadd(mm,datediff(mm,0,getdate()),0) O"}O~lZ[6T
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +w?-#M#
Dateadd(yy,datediff(yy,0,getdate()),0) T9FGuit9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) y[ZVi5) ,
上面的SQL代码只是一个时间段 ,zEPdhTX
Dateadd(wk,datediff(wk,0,getdate()),-1) r:M0#
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Dateadd(wk,datediff(wk,0,getdate()),6) RR2M+vQ
就是表示本周时间段. JmC2buO
下面的SQL的条件部分,就是查询时间段在本周范围内的: dDA,Ps
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) fu
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而在存储过程中 j-d542"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) O03F@v
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) >9y!M'V