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。 lB.n5G
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一、基础 cICfV,j
1、说明:创建数据库 }9&dY!h +
CREATE DATABASE database-name _07$TC1
2、说明:删除数据库 *eX/ZCn
drop database dbname *f_A:`:
3、说明:备份sql server (][-()YV
--- 创建 备份数据的 device .(3ec/i4CF
USE master (L yK o
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \>G}DGz
--- 开始 备份 9Q!Z9n"8~)
BACKUP DATABASE pubs TO testBack g> ~+M
4、说明:创建新表 kdp^{zW}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) BMdZd5!p&
根据已有的表创建新表: tY:
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A:create table tab_new like tab_old (使用旧表创建新表) 57=d;Yg e
B:create table tab_new as select col1,col2... from tab_old definition only K?r
5、说明:删除新表 k/sfak{Q
drop table tabname j=Izwt>
6、说明:增加一个列 +k~0&lZi
Alter table tabname add column col type bE{YK
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。 T]nAz<l),
7、说明:添加主键: Alter table tabname add primary key(col) >239SyC-,
说明:删除主键: Alter table tabname drop primary key(col) boHbiE
8、说明:创建索引:create [unique] index idxname on tabname(col....) fx>U2
删除索引:drop index idxname oOC&w0
注:索引是不可更改的,想更改必须删除重新建。 x/wgD'?
9、说明:创建视图:create view viewname as select statement _ Yc"{d3S
删除视图:drop view viewname 3zu6#3^
10、说明:几个简单的基本的sql语句 3
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选择:select * from table1 where 范围 Ga-cto1Y
插入:insert into table1(field1,field2) values(value1,value2) ,II3b(l
删除:delete from table1 where 范围 LrT EF
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更新:update table1 set field1=value1 where 范围 /|<SD.:
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =,h'}(z_
排序:select * from table1 order by field1,field2 [desc] 0{ ~2mgg h
总数:select count as totalcount from table1 L`X5\D'X
求和:select sum(field1) as sumvalue from table1 a(=lQ(v/?
平均:select avg(field1) as avgvalue from table1 841 y"@*BY
最大:select max(field1) as maxvalue from table1 -
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最小:select min(field1) as minvalue from table1 e([>sAx!1
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11、说明:几个高级查询运算词 "qd|!:bE
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A: UNION 运算符 m C`*#[
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。 Y;%LwDC
B: EXCEPT 运算符 8>Cf}TvErx
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。 \$*CXjh3G
C: INTERSECT 运算符 t$wbwP
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。 r-TrA$k
注:使用运算词的几个查询结果行必须是一致的。 _U-`/r o
12、说明:使用外连接 9}m?E<6&
A、left outer join: @!u{>!~0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 d9BFeq8
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~J&-~<%P}
B:right outer join: J-<_e??
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 /I!62?)-*
C:full outer join: h`dQOH#
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 6<$.Z-,
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二、提升 p:5NMo
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) s1[&WDedM
法一:select * into b from a where 1<>1 NjpWK;L
法二:select top 0 * into b from a jC4>%!{m
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) lwrh4<~\,*
insert into b(a, b, c) select d,e,f from b; IGQBTdPUa
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) At?|[%<`
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Q?1J<(oq9
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {59>U~
4、说明:子查询(表名1:a 表名2:b) 4=/jh: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) !%ju.Xs8
5、说明:显示文章、提交人和最后回复时间 @uCi0P t
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b jH!;}q
6、说明:外连接查询(表名1:a 表名2:b) KFwuz()7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6p*X8j3pW
7、说明:在线视图查询(表名1:a ) rDhQ3iCqo
select * from (SELECT a,b,c FROM a) T where t.a > 1; c:u*-lYmK%
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 eZqEFMBTm
select * from table1 where time between time1 and time2 `Wg"m~l$N
select a,b,c, from table1 where a not between 数值1 and 数值2 _,)_(R ,h
9、说明:in 的使用方法 (
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select * from table1 where a [not] in ('值1','值2','值4','值6') GDSXBa*7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 +pwTM]bV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) H-+U^@w
11、说明:四表联查问题: fmj}NV&ma
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 ..... 4
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12、说明:日程安排提前五分钟提醒 WA~[)S0
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $wp>2
13、说明:一条sql 语句搞定数据库分页 -X!<$<\y;
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 ;!A8A4~nu
14、说明:前10条记录 Z@Zg3AVU
select top 10 * form table1 where 范围 "aF2:E'
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.) F
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q=Mv"~2>B
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 IDT\hTPIs
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?'+]d;UO&
17、说明:随机取出10条数据 cZ|*Zpk
select top 10 * from tablename order by newid() D]fuX|f~ul
18、说明:随机选择记录 v:QUwW
select newid() )'T].kWW
19、说明:删除重复记录 ''@Tke3IG6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) T` h%=u|D
20、说明:列出数据库里所有的表名 PdqvXc
select name from sysobjects where type='U' ?Y3i-jY
21、说明:列出表里的所有的 [*p;+&+/ZM
select name from syscolumns where id=object_id('TableName') 2A;i
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。 %%}l[W
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 AXHY$f|
显示结果: rHB>jN@$
type vender pcs Lv['/!DJ|
电脑 A 1 dN3^PK
电脑 A 1 1C{0 R.
光盘 B 2 C/Tk`C&
光盘 A 2 7*+CX
手机 B 3 M$%ON>Kq
手机 C 3 [mu8V+8@d4
23、说明:初始化表table1 #$xtUCqX
TRUNCATE TABLE table1 pNOE
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24、说明:选择从10到15的记录 ~6n|GxR.[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc PiM(QR
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三、技巧 4"kc(J`c
1、1=1,1=2的使用,在SQL语句组合时用的较多 mc%.
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, nUpj+F#
如: s 0Uid&qE
if @strWhere !='' e}yF2|0FD
begin 9!n95
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Es7
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end s(3u\#P
else m_oUl(pk
begin 'Xwv,
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ~6kF`}5
end $I*}AUp
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我们可以直接写成 #X'-/q`.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @[9
2、收缩数据库 'RKpMdoz
--重建索引 IF6$@Q
DBCC REINDEX 8|)!E`TKSV
DBCC INDEXDEFRAG .8^mA1fmX
--收缩数据和日志 z0/+P
DBCC SHRINKDB 4)tY6ds)r|
DBCC SHRINKFILE HJN GO[*g
3、压缩数据库 1?H;
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dbcc shrinkdatabase(dbname) gU+yqT7=
4、转移数据库给新用户以已存在用户权限 "=s}xAM|A
exec sp_change_users_login 'update_one','newname','oldname' |Jd8ul:&e
go ^g6v#]&WA
5、检查备份集 aSIb0`(3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' `oikSx$vB.
6、修复数据库 =t-Ud^3
ALTER DATABASE [dvbbs] SET SINGLE_USER !9
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GO |OF3O,5z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK vw!7f|Pg ~
GO "KK}}$>
ALTER DATABASE [dvbbs] SET MULTI_USER ,= ApnNUgX
GO S;#:~?dU
7、日志清除 a%m
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SET NOCOUNT ON 13/,^?
DECLARE @LogicalFileName sysname, ffL]_E
@MaxMinutes INT, )yb~ kbe
@NewSize INT 59D'*!l-
USE tablename -- 要操作的数据库名 !Z2h?..O
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 A4@z+ebb l
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zqdkt `
@NewSize = 1 -- 你想设定的日志文件的大小(M) drjNK!XL@
-- Setup / initialize ^2Cqy%x-
DECLARE @OriginalSize int =<H ekiYM
SELECT @OriginalSize = size G`%rnu
FROM sysfiles @JhkUGG]p
WHERE name = @LogicalFileName 6Zn[l,\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + uo]\L^j
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + IrCl\HQN
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =@4,szLO
FROM sysfiles _@XueNU1hS
WHERE name = @LogicalFileName yOlVS@7
CREATE TABLE DummyTrans ]@z!r2[
(DummyColumn char (8000) not null) &77J,\C$:
DECLARE @Counter INT, &2 Yo
@StartTime DATETIME, n^;-&
@TruncLog VARCHAR(255) jbS@6 *_
SELECT @StartTime = GETDATE(), h/\Zq
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q[qX O5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 8BAe6-*S8
EXEC (@TruncLog) Zc_F"KJL
-- Wrap the log if necessary. 6/wC StZ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Kn$E{ F\
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <`SA>P
AND (@OriginalSize * 8 /1024) > @NewSize 1VFCK&
BEGIN -- Outer loop. n-M6~
SELECT @Counter = 0 F-:AT$Ok
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `$1A;wg<
BEGIN -- update TxQsi"0c
INSERT DummyTrans VALUES ('Fill Log') SHPDbBS
DELETE DummyTrans d1g7:s9$0
SELECT @Counter = @Counter + 1 (G+)v[f
END a] c03$f K
EXEC (@TruncLog) ,/p+#|>C=
END Ou4hAm91s
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $> QJ%v9+
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {wSz >,
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' nt>3 i! l
FROM sysfiles /!Ag/SmS!9
WHERE name = @LogicalFileName P|ibUxSA~,
DROP TABLE DummyTrans j07A>G-=
SET NOCOUNT OFF Cd^1E]O0{
8、说明:更改某个表 q/*veL
exec sp_changeobjectowner 'tablename','dbo' 3:WHC3}W
9、存储更改全部表 <bW~!lv
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch <Sd ef^
@OldOwner as NVARCHAR(128), (kX:@9Pn
@NewOwner as NVARCHAR(128) 3;z1Hp2X
AS ]Gm4gd`
DECLARE @Name as NVARCHAR(128) <^>
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DECLARE @Owner as NVARCHAR(128) ~5|R`%
DECLARE @OwnerName as NVARCHAR(128) l=P)$O|=w
DECLARE curObject CURSOR FOR VSUWX1k4%
select 'Name' = name, )Az0.}
'Owner' = user_name(uid) b(@GKH"W
from sysobjects Es}`SIe/
where user_name(uid)=@OldOwner E]vox~xK>
order by name )Dhx6xM[a
OPEN curObject a6h+?Q7uF
FETCH NEXT FROM curObject INTO @Name, @Owner J0&-UnJ
WHILE(@@FETCH_STATUS=0) B)DuikV.D
BEGIN nvQX)Xf
if @Owner=@OldOwner jpYZ)
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begin KIY`3Fl09
set @OwnerName = @OldOwner + '.' + rtrim(@Name) N?rE:0SJ
exec sp_changeobjectowner @OwnerName, @NewOwner 5>S1lyam
end \ 6taC
-- select @name,@NewOwner,@OldOwner {l/`m.Z
FETCH NEXT FROM curObject INTO @Name, @Owner S/eplz;
END -0`n(`2
close curObject er
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deallocate curObject Yevd h<
GO 8.wtv5eZ
10、SQL SERVER中直接循环写入数据 4!ZT_q
declare @i int )j}#6r
set @i=1 )JyB
while @i<30 LrdED[Z
begin >U\P^yU
insert into test (userid) values(@i) ]T5\LNyN
set @i=@i+1 <ir]bQT
end By[M|4a
小记存储过程中经常用到的本周,本月,本年函数 5(1c?biP&
Dateadd(wk,datediff(wk,0,getdate()),-1) :>ca).cjac
Dateadd(wk,datediff(wk,0,getdate()),6) >*B59+1P
Dateadd(mm,datediff(mm,0,getdate()),0) +,7vbs3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) xp^Jp
Dateadd(yy,datediff(yy,0,getdate()),0) 7N OF^/nU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) _ A{F2M
上面的SQL代码只是一个时间段 !%(kMN
Dateadd(wk,datediff(wk,0,getdate()),-1) 9RSviIi$
Dateadd(wk,datediff(wk,0,getdate()),6) t<}N>%ZO
就是表示本周时间段. k=p[Mlic/
下面的SQL的条件部分,就是查询时间段在本周范围内的: t5 ^hZZ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rR{KnM
而在存储过程中 CO,{/
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) B )\;Ja
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) q TWQ!