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。 _A]~`/0;`
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一、基础 K~5(j{Kb8
1、说明:创建数据库 F>@z&a}(
CREATE DATABASE database-name ;%u)~3B$JK
2、说明:删除数据库 u8y('\(
drop database dbname ^'sOWIzeiY
3、说明:备份sql server /h&>tYVio
--- 创建 备份数据的 device J/ vcP
USE master {`L,F
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Rg~[X5
--- 开始 备份 c/3]M>+M
BACKUP DATABASE pubs TO testBack uk.x1*0x
4、说明:创建新表 oX/#Mct{s
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) .M\0+,%/
根据已有的表创建新表: 9'p
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A:create table tab_new like tab_old (使用旧表创建新表) $:D hK
B:create table tab_new as select col1,col2... from tab_old definition only U:IeMf-;
5、说明:删除新表 u/?;J1z:
drop table tabname z]i/hU
6、说明:增加一个列 ue}lAW{q
Alter table tabname add column col type jRjQDK_"ka
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。 ve=1y)
7、说明:添加主键: Alter table tabname add primary key(col) (]<G)+*
说明:删除主键: Alter table tabname drop primary key(col) !P _'n
8、说明:创建索引:create [unique] index idxname on tabname(col....) QlxlT $o}
删除索引:drop index idxname EmcwX4|
注:索引是不可更改的,想更改必须删除重新建。 KH1/B_.\V
9、说明:创建视图:create view viewname as select statement _P]k6z+
删除视图:drop view viewname qjvIp-
10、说明:几个简单的基本的sql语句 s8kkf5bu
选择:select * from table1 where 范围 0`e- ;
插入:insert into table1(field1,field2) values(value1,value2) X_I.f6v{
删除:delete from table1 where 范围 W&a<Q)o*I
更新:update table1 set field1=value1 where 范围 r\{; ~V
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! gB#$"mq,
排序:select * from table1 order by field1,field2 [desc] 7Rom#Kl:
总数:select count as totalcount from table1 ;,LlOR
求和:select sum(field1) as sumvalue from table1 "{(4
平均:select avg(field1) as avgvalue from table1 ?Wp{tB9N0
最大:select max(field1) as maxvalue from table1 hLLg
最小:select min(field1) as minvalue from table1 Wv)2dD2I
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11、说明:几个高级查询运算词 ~ +z'pK~c
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A: UNION 运算符 Q1@V?`rkS{
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。 0IjQqI
B: EXCEPT 运算符 *gzX=*;x+?
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。 4;d9bd)A
C: INTERSECT 运算符 c=HL
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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。 zc-.W2"Hu
注:使用运算词的几个查询结果行必须是一致的。 >U$,/_uMNW
12、说明:使用外连接 G@QZmuj&KH
A、left outer join: xpVYNS{c+|
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 C_Z[ul
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R|AGN*.
B:right outer join: jW+L0RkX
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 H\<C@OkJS}
C:full outer join: fKAG+ t
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 O-vvFl#4
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二、提升 }3!.e
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l4d2i;4BK
法一:select * into b from a where 1<>1 R3$eq
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法二:select top 0 * into b from a ghiFI<)VY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8f |
insert into b(a, b, c) select d,e,f from b; BY$%gIB6>
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) 5X-cDY*|
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |nj%G<
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *(x`cf;k
4、说明:子查询(表名1:a 表名2:b) kqA`d
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) w]\O3'0Js
5、说明:显示文章、提交人和最后回复时间 s?5(E}
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @hWt.qO3s
6、说明:外连接查询(表名1:a 表名2:b) sT3O_20{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }45&s9m=
7、说明:在线视图查询(表名1:a ) J%_
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select * from (SELECT a,b,c FROM a) T where t.a > 1; =2{ ^qvP
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 Jh[fFg]
select * from table1 where time between time1 and time2 c X553&
select a,b,c, from table1 where a not between 数值1 and 数值2 f?_H02j`/E
9、说明:in 的使用方法 e2%Y8ZJG.
select * from table1 where a [not] in ('值1','值2','值4','值6') O- &>Dc
10、说明:两张关联表,删除主表中已经在副表中没有的信息 e ?H`p"l
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) mg*[,_3q33
11、说明:四表联查问题: #G^?4Za
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 ..... Y9 ,KOs
12、说明:日程安排提前五分钟提醒 #Gs] u
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 h 5ST`jZ
13、说明:一条sql 语句搞定数据库分页 $}7/mS@c
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 BfIGw
14、说明:前10条记录 qV.*sdS>
select top 10 * form table1 where 范围 y%\kgWV
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.) sL
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q5/".x^@
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 c ++tk4
(select a from tableA ) except (select a from tableB) except (select a from tableC) }ruBbeQ
17、说明:随机取出10条数据 Yyby 1
select top 10 * from tablename order by newid() izow=}
18、说明:随机选择记录 $AUC#<*C
select newid() o6ec\v!l-
19、说明:删除重复记录 Ylll4w62N
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) O[;>Y'zqC%
20、说明:列出数据库里所有的表名 k 0z2)3L
select name from sysobjects where type='U' `$7j:<c=
21、说明:列出表里的所有的 sC48o'8(
select name from syscolumns where id=object_id('TableName') /A4zR
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ;+`t[ go
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type diGPTV-?$
显示结果: Q\Fgc ;.U
type vender pcs iu2{%S)w
电脑 A 1 o4,W!^n2
电脑 A 1 NB;8 e>8
光盘 B 2 <|~X,g;f
光盘 A 2 YUat}-S
手机 B 3 r%JJ5Al.S
手机 C 3 iZB?5|*
23、说明:初始化表table1 r'uD|T H
TRUNCATE TABLE table1 gN
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24、说明:选择从10到15的记录 \IbGNV`q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?k]^?7GN
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三、技巧 \m~?mg"#
1、1=1,1=2的使用,在SQL语句组合时用的较多 +LCpE$H
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \L-o>O
如: L]3 V)`}
if @strWhere !='' K>Dn#"{Y
begin )" q$g&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -uXf?sTV
end 'kf]l=i[n
else k*d0ws#<l
begin +]
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' \3LP@;Phn
end *JDQaWzBd
我们可以直接写成 $'}rBPA/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere z'Atw"kA
2、收缩数据库 @9lV~,,U
--重建索引 W+d=BnOa8
DBCC REINDEX =VFi}C/
DBCC INDEXDEFRAG %wWJVq}jx
--收缩数据和日志 jT>G8}h
DBCC SHRINKDB ^<49NUB>
DBCC SHRINKFILE 3DRJl,v
3、压缩数据库 z{Z4{&M
dbcc shrinkdatabase(dbname) Z:9xf:g*
4、转移数据库给新用户以已存在用户权限 ,RjE?M%
exec sp_change_users_login 'update_one','newname','oldname' Oo^kV:.)
go q#B=PZ'NA
5、检查备份集 Vea2 oQq
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *;cvG?V
6、修复数据库 m:&go2Y
ALTER DATABASE [dvbbs] SET SINGLE_USER DSjEoWj
GO M#%l}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK V>D8l @
GO AX($LIy9P
ALTER DATABASE [dvbbs] SET MULTI_USER D$@5$./
GO nSY3=Edx=
7、日志清除 LtIp,2GP&_
SET NOCOUNT ON B'}h6ZH
DECLARE @LogicalFileName sysname, gySCK-(y
@MaxMinutes INT, >T84NFdz+
@NewSize INT lTb4quf8I
USE tablename -- 要操作的数据库名 |i_+b@Lul
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4z<nJOEh[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. W]Bc7JM]T+
@NewSize = 1 -- 你想设定的日志文件的大小(M) 'Ur1I"
-- Setup / initialize pmda9V4
DECLARE @OriginalSize int WH|TdU$V
SELECT @OriginalSize = size kU:ge
FROM sysfiles ` /
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WHERE name = @LogicalFileName [B~*88T
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /bdL.Y# V
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6%yt"XmT
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7R5m|h`M
FROM sysfiles 5@QJ+@j|
WHERE name = @LogicalFileName eX`wQoV%
CREATE TABLE DummyTrans HSwC4y}
(DummyColumn char (8000) not null) `JQw]\f4>
DECLARE @Counter INT, 6roq 1=
@StartTime DATETIME, qa-%j +
@TruncLog VARCHAR(255) CFK{.{d]B
SELECT @StartTime = GETDATE(), _uXb 9
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ~8JOPzK
DBCC SHRINKFILE (@LogicalFileName, @NewSize) %f)%FN.S
EXEC (@TruncLog) B*Z}=$1j
-- Wrap the log if necessary. h2jrO9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +{~cX]|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Vh ?5
AND (@OriginalSize * 8 /1024) > @NewSize _tlr8vL
BEGIN -- Outer loop. m@Hg:DY
SELECT @Counter = 0 CwjKz*'[g
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
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BEGIN -- update JU Xo3D~
INSERT DummyTrans VALUES ('Fill Log') t
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DELETE DummyTrans u+lNcyp"MW
SELECT @Counter = @Counter + 1 4 :phq
END C5,\DdCX,
EXEC (@TruncLog) 73j\!x
END k1'd';gQ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !L[$t~z
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + bblEZ%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' %E8HLTEvl
FROM sysfiles ZAJ~Tbm[f
WHERE name = @LogicalFileName l&|Tb8_'
DROP TABLE DummyTrans lLur.f
SET NOCOUNT OFF rF$S
8、说明:更改某个表 h e=A%s
exec sp_changeobjectowner 'tablename','dbo' {3T&6 LA
9、存储更改全部表 Ts\PZQ!q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !k<k]^Z\
@OldOwner as NVARCHAR(128), yxtfyf|9 '
@NewOwner as NVARCHAR(128) v4qpE!W27~
AS ug_c}Nv=Y
DECLARE @Name as NVARCHAR(128) V~_6t{L
DECLARE @Owner as NVARCHAR(128) !a4`SjOgu
DECLARE @OwnerName as NVARCHAR(128) %x./>-[t
DECLARE curObject CURSOR FOR y*Gq VA[
select 'Name' = name, ZcHd.1fXh
'Owner' = user_name(uid) _'|C-j`u$
from sysobjects u+9)B 6O1
where user_name(uid)=@OldOwner $a|>>?8
order by name au E8 ^|
OPEN curObject >guX,hx^
FETCH NEXT FROM curObject INTO @Name, @Owner vA{DF{S4
WHILE(@@FETCH_STATUS=0) ;Kh[6{ W
BEGIN hWiHKR]
if @Owner=@OldOwner F0wW3+G
begin l1.eAs5U
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ?pdN!zOeL
exec sp_changeobjectowner @OwnerName, @NewOwner |.b&\
end x6Tpt^N}
-- select @name,@NewOwner,@OldOwner E#A}2|7,g
FETCH NEXT FROM curObject INTO @Name, @Owner uF ;8B]"
END 2q
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close curObject -UWyBM3c@
deallocate curObject V#B'm?aQ
GO r3Kx
10、SQL SERVER中直接循环写入数据 E<p<"UjcCJ
declare @i int v+i==vxg
set @i=1 <O41M\,
while @i<30 sHPlNwyy
begin S"fqE%
insert into test (userid) values(@i) "AlR%:]24~
set @i=@i+1 <vzU}JA\
end XM3~]
小记存储过程中经常用到的本周,本月,本年函数 rcf#8
Dateadd(wk,datediff(wk,0,getdate()),-1) ^Ge|tBMoKE
Dateadd(wk,datediff(wk,0,getdate()),6) gF]IAZCi
Dateadd(mm,datediff(mm,0,getdate()),0) ;xSlRTNT=6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @7sHFwtar?
Dateadd(yy,datediff(yy,0,getdate()),0) 2h)*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) &m`@6\N(
上面的SQL代码只是一个时间段 :4>LtfA
Dateadd(wk,datediff(wk,0,getdate()),-1) %+dRjG~TB
Dateadd(wk,datediff(wk,0,getdate()),6) SwO8d;e
就是表示本周时间段. !MOcF5M
下面的SQL的条件部分,就是查询时间段在本周范围内的: ?QcS$i
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) /AIFgsaY
而在存储过程中 i7?OZh*f
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 618bbftx{
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) L(/wsw~y*