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。 iN;Pg_Kq
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一、基础 '.A!IGsj
1、说明:创建数据库 8`4M4"lj
CREATE DATABASE database-name PxkV[nbS
2、说明:删除数据库 e(c\ U}&
drop database dbname _4S^'FDo
3、说明:备份sql server "hIYf7r##
--- 创建 备份数据的 device Xoj"rR9|
USE master !>`Q]M`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X~{6$J|]#i
--- 开始 备份 ",#.?vT`
BACKUP DATABASE pubs TO testBack sx,$W3zI'G
4、说明:创建新表 "HOZ2_(o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Sn=6[RQ>P
根据已有的表创建新表: 3smkY
A:create table tab_new like tab_old (使用旧表创建新表) \:vF FK4a
B:create table tab_new as select col1,col2... from tab_old definition only WogUILB
5、说明:删除新表 c{q+h V=
drop table tabname .3
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6、说明:增加一个列 ;n&95t1$
Alter table tabname add column col type k8gH#ENNK
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。 &#p1ogf:
7、说明:添加主键: Alter table tabname add primary key(col) s^kG]7
说明:删除主键: Alter table tabname drop primary key(col) omG2p
8、说明:创建索引:create [unique] index idxname on tabname(col....) &Vlno*
删除索引:drop index idxname )V1XL
注:索引是不可更改的,想更改必须删除重新建。 b?~p/[
9、说明:创建视图:create view viewname as select statement Liqo)m
删除视图:drop view viewname ?ANWI8'_j
10、说明:几个简单的基本的sql语句 s:T%,xS
选择:select * from table1 where 范围 (i&+= +"wn
插入:insert into table1(field1,field2) values(value1,value2) 1/dL-"*0
删除:delete from table1 where 范围 /}:{(Go
更新:update table1 set field1=value1 where 范围 !(d]f0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %YG?7PBB
排序:select * from table1 order by field1,field2 [desc] LjZlKB5C
总数:select count as totalcount from table1 EP>u% ]#
求和:select sum(field1) as sumvalue from table1 t{k:H4
平均:select avg(field1) as avgvalue from table1 !I7$e&Uz@
最大:select max(field1) as maxvalue from table1 ff--y8h
最小:select min(field1) as minvalue from table1 iI GK"}
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11、说明:几个高级查询运算词 WK%cbFq(
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A: UNION 运算符 +Mj6.X
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ; lMv xt:
B: EXCEPT 运算符 0R?1|YnB
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 5`h 6oFxGp
C: INTERSECT 运算符 @c~Z0+Ji
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 >X~B1D,SV7
注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 Ww<Y]H$xZ<
A、left outer join: Ah2@sp,z
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。 a%#UF@I
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 Tm%5:/<8
B:right outer join: -` ]9o3E7H
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。 kowS| c#
C:full outer join: a;o0#I#Si
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。 E ,i^rA m
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二、提升 gawY{Jr8I
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !j!w$
法一:select * into b from a where 1<>1 Y9.3`VX
法二:select top 0 * into b from a 2Zu9?
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7D'\z
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insert into b(a, b, c) select d,e,f from b; BMp'.9Qgm
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) yfl?\X{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #Xg;E3BM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^ :VH?I=
4、说明:子查询(表名1:a 表名2:b) CHnclT
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) K V5
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5、说明:显示文章、提交人和最后回复时间 W8W7<ml0A
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) ()lgd7|+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c EjP;P}_iK
7、说明:在线视图查询(表名1:a ) :WB uU
select * from (SELECT a,b,c FROM a) T where t.a > 1; '#Wx@
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 V]zZb-m=
select * from table1 where time between time1 and time2 'sEnh<
select a,b,c, from table1 where a not between 数值1 and 数值2 OZ`cE5"i
9、说明:in 的使用方法 E%w^q9C
select * from table1 where a [not] in ('值1','值2','值4','值6') XoN~d
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ZU 3Psj
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <H-Nft>O
11、说明:四表联查问题:
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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 ..... QE]'Dc%
12、说明:日程安排提前五分钟提醒 Ts!'>_<Je
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ')xOL=w
13、说明:一条sql 语句搞定数据库分页 !2t7s96
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 CCTU-Xz/
14、说明:前10条记录 +\=g&G,
select top 10 * form table1 where 范围
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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&4s%:_4
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) LL<xygd
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 >a8iY|QY
(select a from tableA ) except (select a from tableB) except (select a from tableC) *fN+wiPD
17、说明:随机取出10条数据 fD!c t; UK
select top 10 * from tablename order by newid() G)vNMl
18、说明:随机选择记录 c7mKE`
select newid() lY,^
19、说明:删除重复记录 eo+<@83
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f-~Y
20、说明:列出数据库里所有的表名 ~[CFs'`(2
select name from sysobjects where type='U' ;L-=z]IR,
21、说明:列出表里的所有的 Sz5t~U=G
select name from syscolumns where id=object_id('TableName') P@N+jS`Vf
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。 /
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 +Tum K.
显示结果: \ eHOHHAGW
type vender pcs eB0exPz%
电脑 A 1 vr;`h/
电脑 A 1 )n&hO_c/
光盘 B 2 56AC%_ g>
光盘 A 2 oc1BOW z
手机 B 3 ?L<B]!9HZt
手机 C 3 ~& -h5=3
23、说明:初始化表table1 [t4v/vQT
TRUNCATE TABLE table1 sVyV|!K
24、说明:选择从10到15的记录 r;Sk[Y5#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KZKE&bTx
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三、技巧 '| i?-(f)
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,`t+X=#
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [c{\el9H
如: FL{Uz+Q
if @strWhere !='' a_Y<daRO
begin x2!R&q8U>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere K P]ar.
end hYoUZ'4
else
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begin <-I69`
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' --$* q"
end %bnXZA2Sx
我们可以直接写成 XIwJhsYZ'9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere J,}h{-Xy`
2、收缩数据库 m?w_
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--重建索引 fJS:46
DBCC REINDEX =x<N+vjXY
DBCC INDEXDEFRAG dlYpbw}W&<
--收缩数据和日志 Y4k2=w:D
DBCC SHRINKDB lDL&":t
DBCC SHRINKFILE ?.e,NHf
3、压缩数据库 >.meecE?Q
dbcc shrinkdatabase(dbname) B=0^Rysg
4、转移数据库给新用户以已存在用户权限 Ge?Wmq>
exec sp_change_users_login 'update_one','newname','oldname' I=dG(?#7%
go x9YQd69
5、检查备份集 $toTMah
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qFm w9\Fn
6、修复数据库 zud_BOq{f
ALTER DATABASE [dvbbs] SET SINGLE_USER Im;%.J
GO ;e?M;-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?[JP[
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GO }$_@yt<{W@
ALTER DATABASE [dvbbs] SET MULTI_USER 8?Zhh.
GO a7g;8t-&
7、日志清除 $INB_/RE
SET NOCOUNT ON wQSan&81Q
DECLARE @LogicalFileName sysname, <- \|>r Q
@MaxMinutes INT, ;wwc;wQ'
@NewSize INT ?X@!jB,Pv
USE tablename -- 要操作的数据库名 G80N8Lm
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4)gG_k
@MaxMinutes = 10, -- Limit on time allowed to wrap log. x7S\-<8
@NewSize = 1 -- 你想设定的日志文件的大小(M) !Gmnck&+
-- Setup / initialize V,-we|"
DECLARE @OriginalSize int &5 "!0
SELECT @OriginalSize = size n3iiW\
FROM sysfiles `*s:[k5k
WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + vhBW1/w&F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _,drOF|e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' hU$aZ
FROM sysfiles n\+c3
WHERE name = @LogicalFileName afrF%!
CREATE TABLE DummyTrans `;85Mo:qJ
(DummyColumn char (8000) not null) #Y=^4 U`
DECLARE @Counter INT, gH//@`6
@StartTime DATETIME, neFwxS?
@TruncLog VARCHAR(255) oxxuw
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SELECT @StartTime = GETDATE(), 'D21A8*N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {;{U@Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) z$Jm1l
EXEC (@TruncLog) A|ZT;\
-- Wrap the log if necessary. JX&U?Z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired WFF?VBT'^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) JV~
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AND (@OriginalSize * 8 /1024) > @NewSize )Q1>j 2&
BEGIN -- Outer loop. <Z^by;d|z
SELECT @Counter = 0 |0[Buh[_:c
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ~$y"Ldrp
BEGIN -- update AQ)gj$
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INSERT DummyTrans VALUES ('Fill Log') 6=f)3!=
DELETE DummyTrans `\( ?^]WLa
SELECT @Counter = @Counter + 1 cO
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END Wk[a|>
EXEC (@TruncLog) AX`Tku
END Lap?L/NS
SELECT 'Final Size of ' + db_name() + ' LOG is ' + %Y&48''"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + M/ 64`lcb
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' j!4{+&Laq
FROM sysfiles kp*v:*
WHERE name = @LogicalFileName I# tlaz#
DROP TABLE DummyTrans -DkD*64wu
SET NOCOUNT OFF ;+~5XLk
8、说明:更改某个表 .`IhxE~mN
exec sp_changeobjectowner 'tablename','dbo' Em!- W5*s
9、存储更改全部表 JvO1tA]ij
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |S!RQ-CF
@OldOwner as NVARCHAR(128), f\2IKpF2
@NewOwner as NVARCHAR(128) 4kL6aSqT
AS 'maX
DECLARE @Name as NVARCHAR(128) %RD\Sb4YV
DECLARE @Owner as NVARCHAR(128) BHr ,jC
DECLARE @OwnerName as NVARCHAR(128) \WiCI:
DECLARE curObject CURSOR FOR %M96m
select 'Name' = name, -m^-p
'Owner' = user_name(uid) pB:XNkxL
from sysobjects rD}g9?ut
where user_name(uid)=@OldOwner T
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order by name boojq{cvYA
OPEN curObject BeUyt
FETCH NEXT FROM curObject INTO @Name, @Owner ] hT\"5&6
WHILE(@@FETCH_STATUS=0) 5M>h[Q"R
BEGIN vaeQ}F
if @Owner=@OldOwner -@XSDfy7S
begin pN^g.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) _%CM<z
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exec sp_changeobjectowner @OwnerName, @NewOwner Z1,rN#p9
end nL?P/ \
-- select @name,@NewOwner,@OldOwner Z=&|__+d
FETCH NEXT FROM curObject INTO @Name, @Owner "lt <$.
END |"}rdOV)
close curObject J_7w_T/
deallocate curObject @V
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GO lc
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10、SQL SERVER中直接循环写入数据 !
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declare @i int ,8384'
set @i=1 eay|>xa2
while @i<30 Un]wP`
begin $q\"d?n
insert into test (userid) values(@i) fizW\f8ai
set @i=@i+1 & R_?6*n
end 9Y3"V3EZ
小记存储过程中经常用到的本周,本月,本年函数 ddgDq0N1j
Dateadd(wk,datediff(wk,0,getdate()),-1) !SK`!/7c?
Dateadd(wk,datediff(wk,0,getdate()),6) X2V+cre
Dateadd(mm,datediff(mm,0,getdate()),0) I7_lKr3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 48 -j
Dateadd(yy,datediff(yy,0,getdate()),0) ;87PP7~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6'r;6T *
上面的SQL代码只是一个时间段 {|oWU8.l
Dateadd(wk,datediff(wk,0,getdate()),-1) -Mr_Ao`E
Dateadd(wk,datediff(wk,0,getdate()),6) B=O zP+
就是表示本周时间段. !\#Wq{p>W*
下面的SQL的条件部分,就是查询时间段在本周范围内的: DCp8rvUI
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $]LS!@ Rm
而在存储过程中 V<
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) I3>8B
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) N'y<<tTA