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。 _R<eWp
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一、基础 H|k!5W^
1、说明:创建数据库 9%WUh-|'p
CREATE DATABASE database-name S.rlF1`
2、说明:删除数据库 MKLnt X
drop database dbname $,4;_4t
3、说明:备份sql server 5n!
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--- 创建 备份数据的 device 3US}('
USE master S%<RV6{aiM
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \.y|=Ql_u
--- 开始 备份 IJ2 ]2FI
BACKUP DATABASE pubs TO testBack tp<uN~rTgh
4、说明:创建新表 3?SofPtc/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) xZW6Hk_
根据已有的表创建新表: *CZvi0&
A:create table tab_new like tab_old (使用旧表创建新表) m d:$OC3
B:create table tab_new as select col1,col2... from tab_old definition only Y~EKMowI&e
5、说明:删除新表 RB.&,1
drop table tabname l4?o0;:)
6、说明:增加一个列 lb ol+O65
Alter table tabname add column col type 7;RhA5M
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。 SO%x=W
7、说明:添加主键: Alter table tabname add primary key(col) :L#t?~
说明:删除主键: Alter table tabname drop primary key(col) j@1cllJkh
8、说明:创建索引:create [unique] index idxname on tabname(col....) eWzD'3h^
删除索引:drop index idxname H7n5k,
注:索引是不可更改的,想更改必须删除重新建。 6*cG>I.Z
9、说明:创建视图:create view viewname as select statement i*B@#;;F
删除视图:drop view viewname u,e'5,`N
10、说明:几个简单的基本的sql语句 {$z )7s
选择:select * from table1 where 范围 BV,P;T0"D
插入:insert into table1(field1,field2) values(value1,value2) Cv862kP
删除:delete from table1 where 范围 FVM:%S
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更新:update table1 set field1=value1 where 范围 ~L(=-B`Ow
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 0yr=$F(]s
排序:select * from table1 order by field1,field2 [desc] .}>d[},F
总数:select count as totalcount from table1 uH[d%y/
求和:select sum(field1) as sumvalue from table1 Z3?,r[
平均:select avg(field1) as avgvalue from table1 V{@
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最大:select max(field1) as maxvalue from table1 Z_Jprp{3h
最小:select min(field1) as minvalue from table1 :=vB|Ch:~
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11、说明:几个高级查询运算词 Ry>c]\a]
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A: UNION 运算符 d!kiWmw,
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。 6,
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B: EXCEPT 运算符 JR{3n*
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。 <Z5ak4P
C: INTERSECT 运算符 RB<LZHZI
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。 | n5F_RL
注:使用运算词的几个查询结果行必须是一致的。 @Aa$k:_
12、说明:使用外连接 !]1X0wo\
A、left outer join: UH/) 4Wg
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 #R$d6N[H
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 |d^r"wbs3
B:right outer join: TJFxo?
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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>S7-X
C:full outer join: R r! PU
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。 uU(G &:@
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二、提升 s\QhCS
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) RK?b/9y
法一:select * into b from a where 1<>1 lxoc.KDtR
法二:select top 0 * into b from a 9t@^P^}=\m
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ?hUC#{
insert into b(a, b, c) select d,e,f from b; &os9K)
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) 92_F8y*D
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 dA>=#/"
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. A5-y+
4、说明:子查询(表名1:a 表名2:b) OJ8 ac6cJ
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) !9=hUpRN
5、说明:显示文章、提交人和最后回复时间 e^kccz2f
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4DI.RK9
6、说明:外连接查询(表名1:a 表名2:b) '7G'R
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <,p|3p3
7、说明:在线视图查询(表名1:a ) *O-1zIlp
select * from (SELECT a,b,c FROM a) T where t.a > 1; Awl4*J~
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 *KNj5>6=
select * from table1 where time between time1 and time2
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select a,b,c, from table1 where a not between 数值1 and 数值2 UwOZBF<
9、说明:in 的使用方法 )&:4//}a
select * from table1 where a [not] in ('值1','值2','值4','值6') =H6"\`W
10、说明:两张关联表,删除主表中已经在副表中没有的信息 vaL+@Kq~&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %7=B?c|
11、说明:四表联查问题: ,73kh
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 ..... )\!_`ob
12、说明:日程安排提前五分钟提醒 wY|&qX,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 W^; wr#
13、说明:一条sql 语句搞定数据库分页 -=BQVJ_dK{
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
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14、说明:前10条记录 nIdB,
select top 10 * form table1 where 范围 V5sH:A7GJ
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.) H59}d
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) : l>&5w;
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 %UZ_wsY\
(select a from tableA ) except (select a from tableB) except (select a from tableC) `|K30hRp:
17、说明:随机取出10条数据 ?"f\"N
select top 10 * from tablename order by newid() vQB;a?)o
18、说明:随机选择记录 2RXU75VY
select newid() =H&{*Ja
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) :0G "EM4
20、说明:列出数据库里所有的表名 .),ql_sXr
select name from sysobjects where type='U' 19-|.9m(
21、说明:列出表里的所有的 (|%YyRaX
select name from syscolumns where id=object_id('TableName') S@i*+&Ot
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。 MmH[ 7R
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 L rV`P)$T
显示结果: _mVq9nBEf
type vender pcs 0'y9HE'e
电脑 A 1 p12'^i |
电脑 A 1 ?U'c;*O-
光盘 B 2 pN# \
光盘 A 2 2u 8z>/G
手机 B 3 lM
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手机 C 3 &}}c>]m
23、说明:初始化表table1 1SIhW:C
TRUNCATE TABLE table1 }T=0]u4,
24、说明:选择从10到15的记录 S9kagiFX\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E>|[@Z
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三、技巧 `s
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1、1=1,1=2的使用,在SQL语句组合时用的较多 $1<V'b[E
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +Hx$ABH
如: [1{#a {4
if @strWhere !='' .ko8`J%%M
begin 1_JtD|Jy
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {2wfv2hQ
end ^q``f%Xt
else ( iM*Y"Y
begin m(Ghe2T:
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #B7_5y^
end qOaI4JP@
我们可以直接写成 _ dFZR
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere o&45y&
2、收缩数据库 7"}<J7"})
--重建索引 +~~FfIzf#
DBCC REINDEX HPl'u'.Hg
DBCC INDEXDEFRAG j8/rd
--收缩数据和日志 I*cB
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DBCC SHRINKDB s5{N+O)~S
DBCC SHRINKFILE Fw,'a
3、压缩数据库 I|jGu9G
dbcc shrinkdatabase(dbname) g+>$_s
4、转移数据库给新用户以已存在用户权限 ]pUf[^4
exec sp_change_users_login 'update_one','newname','oldname' ,>(/}=Z.
go i}SJ
5、检查备份集 DY2r6bcn`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' \-(.cj)?
6、修复数据库 ')C%CAYW
ALTER DATABASE [dvbbs] SET SINGLE_USER ^6&?R?y
GO x3ds{Z$,>(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK GFM$1}
GO >q+o
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ALTER DATABASE [dvbbs] SET MULTI_USER J9s4lsea
GO vY|{CBGbd
7、日志清除 wX(h]X"q
SET NOCOUNT ON paFiuQ
DECLARE @LogicalFileName sysname, d+FS
@MaxMinutes INT, ,_HSvs7-
@NewSize INT z'cVq}vl
USE tablename -- 要操作的数据库名 Glz)-hjJ:n
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 V%k #M
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {#>>dILPr
@NewSize = 1 -- 你想设定的日志文件的大小(M) +#qW 0g
-- Setup / initialize 8@`"Zz M
DECLARE @OriginalSize int Z^t" !oY
SELECT @OriginalSize = size H/!_D f
FROM sysfiles $`7cs}#
WHERE name = @LogicalFileName ZJUTti D
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3GMRH;/w
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Ejc%DSG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5I #L|+
FROM sysfiles TR2X' `:O
WHERE name = @LogicalFileName 9+'QH
CREATE TABLE DummyTrans t~mbe
(DummyColumn char (8000) not null) L,!3
DECLARE @Counter INT, Jpi\n-
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@StartTime DATETIME, "[f"h
@TruncLog VARCHAR(255) fq^D<c{3
SELECT @StartTime = GETDATE(), nXjf,J-T
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &?~OV:r9
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3SbtN3
EXEC (@TruncLog) O{b.-<
-- Wrap the log if necessary. q ld2<W
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired vZEeb j
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) US8pT|/
AND (@OriginalSize * 8 /1024) > @NewSize ;dXQB>Za
BEGIN -- Outer loop. r{DR$jD
SELECT @Counter = 0 8m? 9?OV5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) eK_Q>;k5A
BEGIN -- update |e+8Xz1>
INSERT DummyTrans VALUES ('Fill Log') S`,(10Y
DELETE DummyTrans \
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SELECT @Counter = @Counter + 1 J;Y=oB
END K-D{Z7J^l
EXEC (@TruncLog) Jjt'R`t%t
END &,?bX])
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~G0\57;h
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + DP E NYr
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IyTL|W6
FROM sysfiles t__UqCq~h
WHERE name = @LogicalFileName nC Mv&{~
DROP TABLE DummyTrans
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SET NOCOUNT OFF 9uk}r; %9
8、说明:更改某个表 FD?!bI4
exec sp_changeobjectowner 'tablename','dbo' jJ^p
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9、存储更改全部表 VCOz?Y*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y*ae 5=6(
@OldOwner as NVARCHAR(128), S+c)
@NewOwner as NVARCHAR(128) ~udi=J|
AS b"U{@
DECLARE @Name as NVARCHAR(128) ')pXQ
DECLARE @Owner as NVARCHAR(128) u nE h
DECLARE @OwnerName as NVARCHAR(128) i:ar{ q
DECLARE curObject CURSOR FOR :W'Yt9v)
select 'Name' = name, J23Tst#s
'Owner' = user_name(uid) >;@ _TAF
from sysobjects bn`1JI@S4
where user_name(uid)=@OldOwner D&5>Op4U
order by name 1mT3$Z
OPEN curObject ?L=@Zs
FETCH NEXT FROM curObject INTO @Name, @Owner bLMN9wGOgK
WHILE(@@FETCH_STATUS=0) Rv9oK-S
BEGIN Uloa]X=Im8
if @Owner=@OldOwner //C3tW
begin Wj2s+L7,
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $N$
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exec sp_changeobjectowner @OwnerName, @NewOwner I@dS/
end nic7RN?F<
-- select @name,@NewOwner,@OldOwner ka_]s:>+
FETCH NEXT FROM curObject INTO @Name, @Owner <uGc=Du
END asT*Z"/Q!
close curObject fIOI
deallocate curObject -phwzR\(t
GO J!?hajw7N
10、SQL SERVER中直接循环写入数据 9IFK4>&O6
declare @i int e1'<;;; L
set @i=1 nS xFz!
while @i<30 >kK;IF9h
begin \!HGkmd
insert into test (userid) values(@i) /[f9Z:>V
set @i=@i+1 F?b5 !<5
end
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小记存储过程中经常用到的本周,本月,本年函数 Gc= #
Dateadd(wk,datediff(wk,0,getdate()),-1) .ztO._J7f
Dateadd(wk,datediff(wk,0,getdate()),6) y8T%g(
Dateadd(mm,datediff(mm,0,getdate()),0) m`(5B
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fp^!?u
Dateadd(yy,datediff(yy,0,getdate()),0) ;B[*f?y-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) YVy+1q[
上面的SQL代码只是一个时间段 C3|(XChqC
Dateadd(wk,datediff(wk,0,getdate()),-1) ;>?NH6B,
Dateadd(wk,datediff(wk,0,getdate()),6) ;m/%g{oV
就是表示本周时间段. #R&Dgt
下面的SQL的条件部分,就是查询时间段在本周范围内的: Hm=!;xAFX
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) VEAf,{)Q
而在存储过程中 eNN)2-96
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?+S jt
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) D[)
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