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。 c;t3I},
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一、基础 D>U(&n
1、说明:创建数据库 Ln+ .$ C
CREATE DATABASE database-name pnuwjU-
2、说明:删除数据库 d'Dd66
drop database dbname f2KH&j>~r
3、说明:备份sql server P A*U\
--- 创建 备份数据的 device Q>\DM'{:4
USE master OFcP4hDi
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d7&d
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--- 开始 备份 Ps0<CUyI
BACKUP DATABASE pubs TO testBack eLHhfu;k
4、说明:创建新表 x}`)'a[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) HpeU'0u0VK
根据已有的表创建新表: E)p[^1WC
A:create table tab_new like tab_old (使用旧表创建新表) ^xgPL'
B:create table tab_new as select col1,col2... from tab_old definition only it>l?h7 I
5、说明:删除新表
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drop table tabname X$t!g`
6、说明:增加一个列 j+lcj&V#
Alter table tabname add column col type r>KmrU4Q
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
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7、说明:添加主键: Alter table tabname add primary key(col) cuf]-C1_
说明:删除主键: Alter table tabname drop primary key(col) #IqRu:csp
8、说明:创建索引:create [unique] index idxname on tabname(col....) V!@6Nv
删除索引:drop index idxname SuV3$-);z
注:索引是不可更改的,想更改必须删除重新建。 x=\W TC
9、说明:创建视图:create view viewname as select statement hSps9*y
删除视图:drop view viewname 0;w 4WJJ
10、说明:几个简单的基本的sql语句 siV]NI':|
选择:select * from table1 where 范围 .
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插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 oj?y_0}:^
更新:update table1 set field1=value1 where 范围 "9 vL+Hh
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! UH(w, R`
排序:select * from table1 order by field1,field2 [desc] h y\iot
总数:select count as totalcount from table1 R:^jQ'1
求和:select sum(field1) as sumvalue from table1 #c/K.?
平均:select avg(field1) as avgvalue from table1 BOdlz#&s
最大:select max(field1) as maxvalue from table1 WkpHe
最小:select min(field1) as minvalue from table1 NP!LBB)=Y
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11、说明:几个高级查询运算词 ~Kt+j
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A: UNION 运算符 BoARM{m
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。 80gOh:
B: EXCEPT 运算符 r#}o
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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。 =
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C: INTERSECT 运算符 u<Ch]m+
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。 &I{5f-o*
注:使用运算词的几个查询结果行必须是一致的。 6 pQo_l}
12、说明:使用外连接 olHmRJ
A、left outer join: NQOf\.#g
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。 j(pe6
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 rof9Rxxe-
B:right outer join: ME5M;bz(
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。 PyQ\O*
C:full outer join: d7Cs a
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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。 c[vFh0s"m
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二、提升 NUuIhB+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) T#H-GOY:
法一:select * into b from a where 1<>1 3"Kap/[h
法二:select top 0 * into b from a &< FKcrZ,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) R_:lp\S&
insert into b(a, b, c) select d,e,f from b; ;jKL B^4nX
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) (K ]wk9a
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,a0RI<D
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. fQw=z$
4、说明:子查询(表名1:a 表名2:b) lm{4x~y$h
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) q03nu3uDI
5、说明:显示文章、提交人和最后回复时间 @c>MROlrlF
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .\
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6、说明:外连接查询(表名1:a 表名2:b) =""5
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c je>mAQKi\
7、说明:在线视图查询(表名1:a ) G}]'}FUp
select * from (SELECT a,b,c FROM a) T where t.a > 1; QZL,zI]LL
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 j0=H6Y
select * from table1 where time between time1 and time2 9`&sZ|"3
select a,b,c, from table1 where a not between 数值1 and 数值2 }n,LvA@[0
9、说明:in 的使用方法 1:{+{Yl7
select * from table1 where a [not] in ('值1','值2','值4','值6') =[TXH^.0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 + =U9<8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,o3`O |PiK
11、说明:四表联查问题: x_(K%0+Ca
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... k~QmDq
12、说明:日程安排提前五分钟提醒 A'n7u'6=
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 [_C([o'\KY
13、说明:一条sql 语句搞定数据库分页 Ubwmn!~
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 w[^lxq
14、说明:前10条记录 `0 u)/s$
select top 10 * form table1 where 范围 530Kk<%^}8
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.) ' 1dhdm8
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) S}
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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 T7?z0DKi
(select a from tableA ) except (select a from tableB) except (select a from tableC) MTbCL53!-
17、说明:随机取出10条数据 y8v0>V0)
select top 10 * from tablename order by newid() kWCxc0
18、说明:随机选择记录 h6:|RGF
select newid() M2qor.d
19、说明:删除重复记录 P;IM -]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) W$gjcsv
20、说明:列出数据库里所有的表名 (|tR>R.Wxg
select name from sysobjects where type='U' sv!6zJs
21、说明:列出表里的所有的 _( QW2m?K
select name from syscolumns where id=object_id('TableName') *M$$%G(4
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。 ^*,?x
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 J8&0l&~6
显示结果: &~=d;llkT
type vender pcs ~UwqQD1p
电脑 A 1 }fhGofN$e
电脑 A 1 BMn`t@ !x
光盘 B 2 :p$Q3
光盘 A 2 y
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手机 B 3 F]RZP/D`
手机 C 3 SU. $bsu
23、说明:初始化表table1
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TRUNCATE TABLE table1 +4[Je$qYa
24、说明:选择从10到15的记录 DeQZDY //
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc J[\8:qE
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三、技巧 >ATccv
1、1=1,1=2的使用,在SQL语句组合时用的较多 #Xi9O.
"where 1=1" 是表示选择全部 "where 1=2"全部不选, <CS,v)4,nH
如: @8cn<+"b
if @strWhere !='' i06|P I
begin tR?)C=4,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {CgF{7`
end qt.=
else J(,{ -d-E
begin d(, M
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Z3 dI
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end
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我们可以直接写成 Rvj[Csgi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere U@LIw6B!KL
2、收缩数据库 iu`B8yI
--重建索引 T^2o'_:
DBCC REINDEX =o[H2o
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DBCC INDEXDEFRAG {t('`z
--收缩数据和日志 85:mh\@-G
DBCC SHRINKDB suN}6CI
DBCC SHRINKFILE 'lgS;ItpKu
3、压缩数据库 VH~ZDZ1P
dbcc shrinkdatabase(dbname) 8HWEObRY
4、转移数据库给新用户以已存在用户权限 L,sXJ23.
exec sp_change_users_login 'update_one','newname','oldname' I\=&v^]
go uA\KbA.c;U
5、检查备份集 1L4v X
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' KP
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6、修复数据库 jf=90eJc
ALTER DATABASE [dvbbs] SET SINGLE_USER sGGi7%
GO cu4 |!s`#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO 58PL@H~@0
ALTER DATABASE [dvbbs] SET MULTI_USER 0BP=SCi
GO Co:Rg@i(F
7、日志清除 PWS5s^WM
SET NOCOUNT ON Aj"fkY|Q
DECLARE @LogicalFileName sysname, zHXb[$Q
@MaxMinutes INT, pH396GFIW
@NewSize INT 4BJ w+EV8
USE tablename -- 要操作的数据库名 oK2j PP
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 J+qcA}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Nbt.y 'd
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]q|U0(q9
-- Setup / initialize /)V8X#,
DECLARE @OriginalSize int w(q\75
SELECT @OriginalSize = size 1HeE$
FROM sysfiles JiX-t\V ~
WHERE name = @LogicalFileName zoau5t
SELECT 'Original Size of ' + db_name() + ' LOG is ' + !Ic~_7"
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + p$$0**p!`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' t'HrI-x
FROM sysfiles >oyZD^gj
WHERE name = @LogicalFileName PC& (1kJ
CREATE TABLE DummyTrans KWn.
(DummyColumn char (8000) not null) :?\Je+iA
DECLARE @Counter INT, s<8|_Dt
@StartTime DATETIME, X7)B)r}AG
@TruncLog VARCHAR(255) ['aiNhlbt
SELECT @StartTime = GETDATE(), xsx0ZovhY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' C=DC g
DBCC SHRINKFILE (@LogicalFileName, @NewSize) `m-7L
EXEC (@TruncLog) E~`<n]{G-C
-- Wrap the log if necessary. ?b?YiK&yz
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired AN+S6t
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) o_.`&Q6n
AND (@OriginalSize * 8 /1024) > @NewSize %WFZ&>en&
BEGIN -- Outer loop. YDGW]T]i ?
SELECT @Counter = 0 I=7 YAm[W
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 35~1$uRA
BEGIN -- update F?4&qbdD
INSERT DummyTrans VALUES ('Fill Log') i5czm?x
DELETE DummyTrans UQJ
SELECT @Counter = @Counter + 1 f<Yg_ TG
END wU&vkb)k
EXEC (@TruncLog) :\|<7n
END y~py+:_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <p#+('N`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !InC8+be
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 77%I%<#
FROM sysfiles %"AB\lL.
WHERE name = @LogicalFileName P"Y7N?\](
DROP TABLE DummyTrans >'&|{s[m
SET NOCOUNT OFF R(#ZaFuo[
8、说明:更改某个表 /Hyi/D{ W
exec sp_changeobjectowner 'tablename','dbo' +\25ynM
9、存储更改全部表 gO_d!x*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )8V=!73
@OldOwner as NVARCHAR(128), G4J)o?:m@
@NewOwner as NVARCHAR(128) n fMU4(:
AS mfr7w+DK
DECLARE @Name as NVARCHAR(128) ,xy$h }g
DECLARE @Owner as NVARCHAR(128) .\"8H1I\T
DECLARE @OwnerName as NVARCHAR(128) ?PU7xO;_
DECLARE curObject CURSOR FOR = Tq\Ag:
select 'Name' = name, =dY!-#yg!
'Owner' = user_name(uid) KKNQ+'?
from sysobjects 8]l(D
where user_name(uid)=@OldOwner \s,~|0_V
order by name v=E(U4v9e
OPEN curObject 7K
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FETCH NEXT FROM curObject INTO @Name, @Owner c{})Z=
WHILE(@@FETCH_STATUS=0) F;Bq[V)R
BEGIN SH6T\}X:
if @Owner=@OldOwner ??,/85lM
begin VB}^&{t)!
set @OwnerName = @OldOwner + '.' + rtrim(@Name) `4a9<bG
exec sp_changeobjectowner @OwnerName, @NewOwner u56WB9Z
end \y+@mJWa
-- select @name,@NewOwner,@OldOwner <!derr-K
FETCH NEXT FROM curObject INTO @Name, @Owner I$oqFF|D
END d,0Klew
close curObject N$<R6DU]K
deallocate curObject J(Zz^$8]<?
GO }KR"0G[f
10、SQL SERVER中直接循环写入数据 4Xe8j55
declare @i int iB5'mb*
set @i=1 %ZGG6Xgw
while @i<30 m[Cp
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begin #2?3B
insert into test (userid) values(@i) @
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set @i=@i+1 jh/aK_Q,w
end ,7SqRY,+
小记存储过程中经常用到的本周,本月,本年函数 :rEZR `
Dateadd(wk,datediff(wk,0,getdate()),-1) !PJp()
Dateadd(wk,datediff(wk,0,getdate()),6) sv+6#
Dateadd(mm,datediff(mm,0,getdate()),0) E>bpq^;r
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) KDLrt
Dateadd(yy,datediff(yy,0,getdate()),0) !Mj28
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 3%
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上面的SQL代码只是一个时间段 Lm'+z97
Dateadd(wk,datediff(wk,0,getdate()),-1) oh,29Gg
Dateadd(wk,datediff(wk,0,getdate()),6) FA}y"I'W
就是表示本周时间段. ? w@)3Z=u
下面的SQL的条件部分,就是查询时间段在本周范围内的: 9~4@AGL
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) QNGp+xUHJ9
而在存储过程中 E*d UJ.>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) #S"s8wdD
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \qtdbi|Y