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。 Sm{idky)[
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一、基础 X*/jna"*
1、说明:创建数据库 9H`Q
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CREATE DATABASE database-name gM '_1zs
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2、说明:删除数据库 ^F/N-!}q
drop database dbname +<(N]w*
3、说明:备份sql server PH^AT<U:T
--- 创建 备份数据的 device !D!Q]M5oU
USE master zvL;.U
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' MZv In ZS
--- 开始 备份 h:}oUr8
BACKUP DATABASE pubs TO testBack vm_+U*%c
4、说明:创建新表 k7'_
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) "l"zbW WOH
根据已有的表创建新表: lo5,E(7~h
A:create table tab_new like tab_old (使用旧表创建新表) $~75/
B:create table tab_new as select col1,col2... from tab_old definition only 'D;v>r
5、说明:删除新表 [8v v[n/
drop table tabname !X*+Ct^
6、说明:增加一个列 Vr+X!DeY
Alter table tabname add column col type WnyEdYA
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 RQ;pAO
7、说明:添加主键: Alter table tabname add primary key(col) KC[ql}JP
说明:删除主键: Alter table tabname drop primary key(col) oYG9i=lZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) <j+DY@*
删除索引:drop index idxname bx#GOK-
注:索引是不可更改的,想更改必须删除重新建。 /PafIq
9、说明:创建视图:create view viewname as select statement ZBUEg7c
删除视图:drop view viewname x* ?-KS|
10、说明:几个简单的基本的sql语句 !?,7Cu.5#6
选择:select * from table1 where 范围 |@`F!bnLr
插入:insert into table1(field1,field2) values(value1,value2) iimTr_TEt
删除:delete from table1 where 范围 @FKm_q
更新:update table1 set field1=value1 where 范围 E3@G^Y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4V@raI-
排序:select * from table1 order by field1,field2 [desc] n6Je5fE
总数:select count as totalcount from table1 i 3?=up!
求和:select sum(field1) as sumvalue from table1 dkVF
平均:select avg(field1) as avgvalue from table1 rVB,[4N
最大:select max(field1) as maxvalue from table1 .B_LQ;0:
最小:select min(field1) as minvalue from table1 jdqVS @SD
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11、说明:几个高级查询运算词 .jA'BF.
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A: UNION 运算符 XHKiz2Pc1
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 j")#"& m
B: EXCEPT 运算符 I|8'#QX
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ^yL6A1
C: INTERSECT 运算符 2.)xWCG
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 VRV*\*~$
注:使用运算词的几个查询结果行必须是一致的。 3M\~#>
12、说明:使用外连接 +GqK$B(x7
A、left outer join: AqnDsr!
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ,<Zu4bww
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,j E'd'$
B:right outer join: T5H[~b|9-
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。 T;!: A
C:full outer join: LS;j]!CU
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。 1?%Q"*Y&
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二、提升 :59fb"^$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) @-ps[b`z
法一:select * into b from a where 1<>1 ?&A)%6` ~
法二:select top 0 * into b from a w*#B_6bG
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) HEh,Cf7`'
insert into b(a, b, c) select d,e,f from b; J< Ljg<t+
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) *9Ta0e*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 w{TZN{Y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @pq2Z^SQ H
4、说明:子查询(表名1:a 表名2:b) cBcfGNTJ~
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) 9n9Z
5、说明:显示文章、提交人和最后回复时间 t~_vzG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ggn C #$
6、说明:外连接查询(表名1:a 表名2:b) wzX(]BG
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c w(Jf;[o
7、说明:在线视图查询(表名1:a ) pV:;!+
select * from (SELECT a,b,c FROM a) T where t.a > 1; X?'Sh XI
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 "}ibH{$lM
select * from table1 where time between time1 and time2 m-T@Og
select a,b,c, from table1 where a not between 数值1 and 数值2 jR1t&UD3Y
9、说明:in 的使用方法 '^mCLfo0}
select * from table1 where a [not] in ('值1','值2','值4','值6') tV.qdy/]}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8.JFQ/)i
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $[(amj-;l
11、说明:四表联查问题: 7 6 nrDE
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... +\Uq=@
12、说明:日程安排提前五分钟提醒 Q+bZZMK5,U
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "-
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13、说明:一条sql 语句搞定数据库分页 |z.x M>
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 E3hql3=
14、说明:前10条记录 p}}pq~EH/
select top 10 * form table1 where 范围 &k53*Wo
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) [Ey[A|g
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) a9LK}xc={
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 O2;iY_P7lV
(select a from tableA ) except (select a from tableB) except (select a from tableC) : ;l9to
17、说明:随机取出10条数据 ]? 2xS?vd
select top 10 * from tablename order by newid() s|HpN
18、说明:随机选择记录 ~V34j:
select newid() _L8|ZV./
19、说明:删除重复记录 z3Id8G&>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) @~p;.=1]F
20、说明:列出数据库里所有的表名 oyw*Z_ 9~
select name from sysobjects where type='U' a%nksuP3
21、说明:列出表里的所有的 =:fN
select name from syscolumns where id=object_id('TableName') U~3uu&/r
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 >;qAj!'
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type }^Ymg7wA
显示结果: /FJ.W<hw
type vender pcs 1Jm'9iy3
电脑 A 1 E^s<5BC;
电脑 A 1 meF.`fh
光盘 B 2 xxy
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光盘 A 2 b?^CnMO
手机 B 3 CU`yi.)T{
手机 C 3 ]9A@iA
23、说明:初始化表table1 DjLSl,Z
TRUNCATE TABLE table1 xVnk]:c
24、说明:选择从10到15的记录 )t#>fnN
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]#NJ[IZb
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三、技巧 Q$bi:EyJXc
1、1=1,1=2的使用,在SQL语句组合时用的较多 I@/s&$H`l
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Sgp1p}
如: hnYL<<AA
if @strWhere !='' r'F)8%
begin C}'Tmi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {D{'
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end D`4>Wh/H
else D`9 a"o
begin &"gQrBa
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #r,LV}*qg
end pLiGky
我们可以直接写成 8pXului
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9cqq"-$G`
2、收缩数据库 2%Mgg,/~
--重建索引 $-w&<U$E
DBCC REINDEX "7z1V{ ;Y
DBCC INDEXDEFRAG 0Z4o3r[
--收缩数据和日志 w;p~|!
DBCC SHRINKDB alp}p
DBCC SHRINKFILE Ss~yy0
3、压缩数据库 k>.n[`>$6|
dbcc shrinkdatabase(dbname) hU|TP3*
4、转移数据库给新用户以已存在用户权限 bC h
exec sp_change_users_login 'update_one','newname','oldname' 'kb|!
go -\|S=<
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5、检查备份集 |Y tZOQu
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3;%dn\
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6、修复数据库 360b`zS
ALTER DATABASE [dvbbs] SET SINGLE_USER %G`GdG}T
GO ^'G,sZ6'Nh
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1@Gmzh
GO o"gtWAGH
ALTER DATABASE [dvbbs] SET MULTI_USER 0ZAT;ea B
GO ]EWEW*'j
7、日志清除 w D}g\{P
SET NOCOUNT ON /idrbc
DECLARE @LogicalFileName sysname, 5jey%)=
@MaxMinutes INT, 0!tw)HR%
@NewSize INT ~Gj%z+<
USE tablename -- 要操作的数据库名 'DdR2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "6t#
@MaxMinutes = 10, -- Limit on time allowed to wrap log. V48o+ O
@NewSize = 1 -- 你想设定的日志文件的大小(M) uGz>AW8a3
-- Setup / initialize vuoD~ =z
DECLARE @OriginalSize int [/Vi*Z
SELECT @OriginalSize = size &YOks.k
FROM sysfiles 1yd}F`{8UF
WHERE name = @LogicalFileName "CTK%be{q/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MJ_]N+
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + cii!
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5fvY#6;
FROM sysfiles X3zpU7`Av+
WHERE name = @LogicalFileName [XbNZ6
CREATE TABLE DummyTrans %8c2d
(DummyColumn char (8000) not null) CzfGb4
DECLARE @Counter INT, a,ZmDkzuv
@StartTime DATETIME, ;)XB'
@TruncLog VARCHAR(255) G$oi>zt3
SELECT @StartTime = GETDATE(), mx=2lL`
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Yc3Rq4I'G
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ~YQH]
EXEC (@TruncLog) :~wU/dEEiz
-- Wrap the log if necessary. P*:9u>
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /v-:ca)7mI
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) &|YJ?},
AND (@OriginalSize * 8 /1024) > @NewSize |kc#=b@l
BEGIN -- Outer loop. _^MkC}8
SELECT @Counter = 0 *LOUf7`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) xcM*D3
BEGIN -- update OzA'd\|
INSERT DummyTrans VALUES ('Fill Log') (iJ9ekB
DELETE DummyTrans xe@11/F
SELECT @Counter = @Counter + 1 J^gElp
END L/KiE+Y
EXEC (@TruncLog) |PxTm
END UlQS]f~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + tDQuimYu7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,)35Vi;.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^_ST#fFS
FROM sysfiles <,+nS%a
WHERE name = @LogicalFileName &xLCq&j1
DROP TABLE DummyTrans hF^y4v|5
SET NOCOUNT OFF tl"?AQcBR
8、说明:更改某个表 QzilivJf
exec sp_changeobjectowner 'tablename','dbo' yFY:D2
9、存储更改全部表 ,GUOq!z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /Bs42uJ3
@OldOwner as NVARCHAR(128), %U?1Gf e
@NewOwner as NVARCHAR(128) G7NRpr
AS []l2
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DECLARE @Name as NVARCHAR(128) [ f;o3
DECLARE @Owner as NVARCHAR(128) I[w;soI
DECLARE @OwnerName as NVARCHAR(128) =;(y5c
DECLARE curObject CURSOR FOR bnZ~jOHl
select 'Name' = name, py }`thx
'Owner' = user_name(uid) >_|$7m.?n[
from sysobjects O6"S=o&
where user_name(uid)=@OldOwner 6%a:^f]
order by name @8eQ|.q]Q
OPEN curObject u:w
FETCH NEXT FROM curObject INTO @Name, @Owner LTw.w:"J
WHILE(@@FETCH_STATUS=0) d;hv_h
BEGIN s2`Qh9R
if @Owner=@OldOwner -*[:3%
begin _lMSW6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) i_f\dkol
exec sp_changeobjectowner @OwnerName, @NewOwner ?k$'po*Eq
end y8j6ttQv=t
-- select @name,@NewOwner,@OldOwner RdqB^>X
FETCH NEXT FROM curObject INTO @Name, @Owner qV5lv-p
END YhQ%S}
close curObject N;S1s0FN
deallocate curObject @@V{W)rl
GO qO{Yr$V%
10、SQL SERVER中直接循环写入数据 `6xr:s
declare @i int )skz_a}]8
set @i=1 ^m['VK#?
while @i<30 ''Hx&
begin /Ref54
insert into test (userid) values(@i) N|e#&
set @i=@i+1 ?/q\S
end 4o|<zn
小记存储过程中经常用到的本周,本月,本年函数 UvF5u(o
Dateadd(wk,datediff(wk,0,getdate()),-1) mqK}yK^P]
Dateadd(wk,datediff(wk,0,getdate()),6) @!Rklhb
Dateadd(mm,datediff(mm,0,getdate()),0) } fJLY\
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) #Q1}h
Dateadd(yy,datediff(yy,0,getdate()),0) &4{!5r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ;6M [d
上面的SQL代码只是一个时间段 z\`tnz7>$
Dateadd(wk,datediff(wk,0,getdate()),-1) \:4SN&I~
Dateadd(wk,datediff(wk,0,getdate()),6) |8?DQhd}
就是表示本周时间段. x|$|~6f=n
下面的SQL的条件部分,就是查询时间段在本周范围内的: X/ lmj_v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) tID=I0D
而在存储过程中 "\+.S]~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) C7FxV2
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) T^icoX=c4