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。 ? _g1*@pA
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一、基础 VDbI-P&c
1、说明:创建数据库 P"_$uO( 5x
CREATE DATABASE database-name JC#>Td
2、说明:删除数据库 3c3OG.H$8
drop database dbname wJ+Aw
3、说明:备份sql server Ysi
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--- 创建 备份数据的 device -JT/9IQ
USE master Uf\nFB? ^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %|"g/2sF[G
--- 开始 备份 ihCIh6
BACKUP DATABASE pubs TO testBack :6{`~=
4、说明:创建新表 )|bC^{kH!l
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) nV_8Ke
根据已有的表创建新表: d3;qsUh$yv
A:create table tab_new like tab_old (使用旧表创建新表) x=Hndx^
B:create table tab_new as select col1,col2... from tab_old definition only Q.U$nph\%d
5、说明:删除新表 P\nC?!Q%c
drop table tabname "xJ 0 vlw
6、说明:增加一个列 %9v@0}5V
Alter table tabname add column col type <Fz~7WVd
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 (C;I*cv
7、说明:添加主键: Alter table tabname add primary key(col) HQP}w%8x
说明:删除主键: Alter table tabname drop primary key(col) vZj`|
8、说明:创建索引:create [unique] index idxname on tabname(col....) \G|%Zw|
删除索引:drop index idxname v(]]_h
注:索引是不可更改的,想更改必须删除重新建。 .dMVoG5
9、说明:创建视图:create view viewname as select statement : 9t4s#.
删除视图:drop view viewname a->3`c
10、说明:几个简单的基本的sql语句 XT>.`, sv
选择:select * from table1 where 范围 lB91An
插入:insert into table1(field1,field2) values(value1,value2) R&f^+0%f
删除:delete from table1 where 范围 E:`v+S_h
更新:update table1 set field1=value1 where 范围 %@"!8Y(j
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ]D2udeg
排序:select * from table1 order by field1,field2 [desc] jE2}p-2Q0
总数:select count as totalcount from table1 kgdT7
求和:select sum(field1) as sumvalue from table1 R(Kk{c:-@
平均:select avg(field1) as avgvalue from table1 IiBD?}
最大:select max(field1) as maxvalue from table1 q`NXJf=sc
最小:select min(field1) as minvalue from table1 {'En\e
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11、说明:几个高级查询运算词 v
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A: UNION 运算符 +HT1 ct+dI
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 -_C#wtC
B: EXCEPT 运算符 Gq<X4C#|
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 D]G)j
C: INTERSECT 运算符 ao_4m SB
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 jnB~sbyA
注:使用运算词的几个查询结果行必须是一致的。 EZ;"'4;W
12、说明:使用外连接 WI> P-D
A、left outer join: `o]g~AKX
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 #|GSQJ$F)`
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 e= vsuqGT
B:right outer join: eB>s=}|
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。 ew _-Eb
C:full outer join: ?<Wb@6kh`
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。 w;UqEC V
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二、提升 yXI >I
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'H8(=9O1d
法一:select * into b from a where 1<>1 ",aTWQgN
法二:select top 0 * into b from a tVrY3)c
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) YOr:sb
insert into b(a, b, c) select d,e,f from b; GeszgtK{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) Q\ /uKQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =@2FX&&E_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 7>XDNI
4、说明:子查询(表名1:a 表名2:b) c;0Vs,DUmG
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) j>Iaq"
5、说明:显示文章、提交人和最后回复时间 "tjLc6Xl^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Wq*b~Lw
6、说明:外连接查询(表名1:a 表名2:b) BrRL7xX
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c K~=UUB
7、说明:在线视图查询(表名1:a ) sJwyj D$b
select * from (SELECT a,b,c FROM a) T where t.a > 1; /sM~Uq?
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 AfeCK1mC @
select * from table1 where time between time1 and time2 fXI:Y8T
select a,b,c, from table1 where a not between 数值1 and 数值2 DejA4XdW
9、说明:in 的使用方法 oi}i\:
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select * from table1 where a [not] in ('值1','值2','值4','值6') ~qe%Yq
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7dsefNPb
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 8
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11、说明:四表联查问题: 3(TsgP>`
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... dL7E<?l
12、说明:日程安排提前五分钟提醒 Y!iZW
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8k
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13、说明:一条sql 语句搞定数据库分页 <)+y=m\eJ
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 !EUan
14、说明:前10条记录 sf&]u;^DY
select top 10 * form table1 where 范围 V%$/#sza
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.) -*5Rnx|Y{
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .920{G?l5
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 bR@p<;G|
(select a from tableA ) except (select a from tableB) except (select a from tableC) ]smkTo/
17、说明:随机取出10条数据 qC
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select top 10 * from tablename order by newid() [Nn`l,
18、说明:随机选择记录 }neY<{z
select newid() c'/l,k
19、说明:删除重复记录 |5Xq0nvCe
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) U9b?i$
20、说明:列出数据库里所有的表名 ~4"qV_M
select name from sysobjects where type='U' WAdCF-S
21、说明:列出表里的所有的 4pw6bK,s2\
select name from syscolumns where id=object_id('TableName') q6YX M
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。 )K &(
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 MSf;ZB
显示结果: ;M"9$M'
type vender pcs F:x [
电脑 A 1 h=;{oY<V)?
电脑 A 1 w$JvB5O
光盘 B 2 H":oNpfb
光盘 A 2 3R+|5Uq8~
手机 B 3 2-Y<4'>
手机 C 3 TB0
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23、说明:初始化表table1 !K|5bK
TRUNCATE TABLE table1 (5]}5W*
24、说明:选择从10到15的记录 <b,~:9*?
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc oudxm[/U
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三、技巧 )1X#*mCxk
1、1=1,1=2的使用,在SQL语句组合时用的较多 ZP{*.]Qu
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '7O3/GDK
如: vVOh3{e|
if @strWhere !='' 13taFVdU
begin $Xq!L
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1GzAG;UUo6
end ,v"YqD+GC5
else 6Ybg^0m
begin / m=HG^!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -'6Dg
end yPq'( PV
我们可以直接写成 AK@9?_D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /Rl6g9}
2、收缩数据库 3Z1CWzq(
--重建索引
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DBCC REINDEX ` V##Y
DBCC INDEXDEFRAG .V,@k7U,V
--收缩数据和日志 FSND>\>
DBCC SHRINKDB p,#o<W
DBCC SHRINKFILE ob8qe,_'
3、压缩数据库 4:FK;~wM&x
dbcc shrinkdatabase(dbname) ~@}Bi@*
4、转移数据库给新用户以已存在用户权限 5{g?,/(
exec sp_change_users_login 'update_one','newname','oldname' %7|9sQ:
go `nu''B
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5、检查备份集 FJMrs[
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' \-g)T}g,I
6、修复数据库 .mR8q+I6
ALTER DATABASE [dvbbs] SET SINGLE_USER <7~'; K
GO A}l3cP;
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WPQ fhr#|
GO a|X a3E
ALTER DATABASE [dvbbs] SET MULTI_USER ui?
GO &v@a5 L
7、日志清除 c
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SET NOCOUNT ON
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DECLARE @LogicalFileName sysname,
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@MaxMinutes INT, m;,N)<~
@NewSize INT mHRiugb!
USE tablename -- 要操作的数据库名 PpzP 7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7<*yS310
@MaxMinutes = 10, -- Limit on time allowed to wrap log. s%W C/ZK
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,y#Kv|R
-- Setup / initialize P5UL4uyl
DECLARE @OriginalSize int F%RRd/'
SELECT @OriginalSize = size |!4K!_y
FROM sysfiles o4Om}]Ti
WHERE name = @LogicalFileName c24dSNJg,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ln6d<;
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + g%=z_
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' I`!<9OTBj
FROM sysfiles DW[N|-L
WHERE name = @LogicalFileName lgk.CC
CREATE TABLE DummyTrans e~=;c
(DummyColumn char (8000) not null) GB=X5<;
DECLARE @Counter INT, 9P+-#B
@StartTime DATETIME, t7aefV&_,
@TruncLog VARCHAR(255) cPlZXf
SELECT @StartTime = GETDATE(), glDu2a,Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' fumm<:<CLO
DBCC SHRINKFILE (@LogicalFileName, @NewSize) J cd-
EXEC (@TruncLog)
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-- Wrap the log if necessary. ``hf=`We
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1G^`-ri6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) YIG~MP
AND (@OriginalSize * 8 /1024) > @NewSize I=`U7Bis"
BEGIN -- Outer loop. W_"sM0
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SELECT @Counter = 0 k5'Vy8q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \"P%`C
BEGIN -- update b gK}-EU
INSERT DummyTrans VALUES ('Fill Log') [M=7M}f;
DELETE DummyTrans Q' {ML4
SELECT @Counter = @Counter + 1 )"7iJb<E
END I&x=;
EXEC (@TruncLog) L 0TFo_
END p8Qk'F=h
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 'a@/vx&J
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + V_ .5b&@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' | ATvS2
FROM sysfiles 8p 'L#Q.
WHERE name = @LogicalFileName u04kF^
DROP TABLE DummyTrans 52Z2]T
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SET NOCOUNT OFF "#2a8#
8、说明:更改某个表 #lL^?|M
exec sp_changeobjectowner 'tablename','dbo' )q8p k2
9、存储更改全部表 6d<r= C=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 2} /aFR
@OldOwner as NVARCHAR(128), y51e%n$
@NewOwner as NVARCHAR(128) u}macKJmp\
AS 7x|9n
DECLARE @Name as NVARCHAR(128) s+$ Q}|?u
DECLARE @Owner as NVARCHAR(128)
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DECLARE @OwnerName as NVARCHAR(128) ; F"g$_D0
DECLARE curObject CURSOR FOR *&^Pj%DX
select 'Name' = name, B"1c
'Owner' = user_name(uid) y.mda:$~=
from sysobjects c tZ uA+
where user_name(uid)=@OldOwner wDal5GJp
order by name 2lH&
OPEN curObject =(j1rW!
FETCH NEXT FROM curObject INTO @Name, @Owner |6sp/38#p
WHILE(@@FETCH_STATUS=0) _Xe>V0
BEGIN Tztu}t]N
if @Owner=@OldOwner ;"5&b!=t
begin M=@:ZQ^!
set @OwnerName = @OldOwner + '.' + rtrim(@Name) K7_UP&`=J
exec sp_changeobjectowner @OwnerName, @NewOwner 'T*&'RQr
end &
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-- select @name,@NewOwner,@OldOwner qd ~BnR$=
FETCH NEXT FROM curObject INTO @Name, @Owner V1N3iI
END AUG#_HE]k
close curObject xX&+WR
deallocate curObject Cn34b_Sbd
GO cJ=6r
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10、SQL SERVER中直接循环写入数据 M6"PX *K
declare @i int S%;O+eFYb
set @i=1 i
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while @i<30 iy.p n
begin @alK;\
insert into test (userid) values(@i) zZPO&akB"
set @i=@i+1 :1QI8%L'$i
end =7=]{Cx[
小记存储过程中经常用到的本周,本月,本年函数 Uiw2oi&_
Dateadd(wk,datediff(wk,0,getdate()),-1) 3wF;GG
Dateadd(wk,datediff(wk,0,getdate()),6) nfbR
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Dateadd(mm,datediff(mm,0,getdate()),0) l
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @Md/Q~>
Dateadd(yy,datediff(yy,0,getdate()),0) w3ResQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) jp%S3)
上面的SQL代码只是一个时间段 `KoV_2|
Dateadd(wk,datediff(wk,0,getdate()),-1) "<N*"euH
Dateadd(wk,datediff(wk,0,getdate()),6) 8b&/k8i:
就是表示本周时间段. VPJElRSH
下面的SQL的条件部分,就是查询时间段在本周范围内的: w,.TTTad
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) e8a+2.!&\
而在存储过程中 V+Y%v.F
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) sUO`u qZV
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Di6 ?[(8