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{8g9a4
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一、基础 y <21~g=
1、说明:创建数据库 V\><6v
CREATE DATABASE database-name sr,8Qd0M
2、说明:删除数据库 h7W<$\P
drop database dbname B6a
3、说明:备份sql server 8:(e~?
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--- 创建 备份数据的 device 2JRX ;s~
USE master * d[sja+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' RjCEo4b-.H
--- 开始 备份 79(Px2H2
BACKUP DATABASE pubs TO testBack f<~S0[H
4、说明:创建新表 }>u<,
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~C2[5r{So
根据已有的表创建新表: 5U&?P
A:create table tab_new like tab_old (使用旧表创建新表) &8wluOs/5
B:create table tab_new as select col1,col2... from tab_old definition only 3sq(FsT
5、说明:删除新表 *6%r2l'kZ
drop table tabname '@+a]kCMev
6、说明:增加一个列 ;;l-E>X0
Alter table tabname add column col type |yow(2(F@
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 <swYo<?J#
7、说明:添加主键: Alter table tabname add primary key(col) [6t!}q
说明:删除主键: Alter table tabname drop primary key(col) |#!P!p}
8、说明:创建索引:create [unique] index idxname on tabname(col....) wNm~H
删除索引:drop index idxname !NFP=m1
注:索引是不可更改的,想更改必须删除重新建。 r6eApKZ>f6
9、说明:创建视图:create view viewname as select statement 0?nm`9v6
删除视图:drop view viewname ,=kQJ|
10、说明:几个简单的基本的sql语句 |F#L{=B
选择:select * from table1 where 范围 t{)J#8:g
插入:insert into table1(field1,field2) values(value1,value2) CK+_T}+-
删除:delete from table1 where 范围 m`lsUN,
更新:update table1 set field1=value1 where 范围 Z}'"c9oB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )Dq/fW
排序:select * from table1 order by field1,field2 [desc] :.M"M$MRp8
总数:select count as totalcount from table1 @z)_m!yV1
求和:select sum(field1) as sumvalue from table1 HNtl>H
平均:select avg(field1) as avgvalue from table1 ?rn#S8nNx<
最大:select max(field1) as maxvalue from table1 y7CrH=^jc
最小:select min(field1) as minvalue from table1 ()v{HBi
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11、说明:几个高级查询运算词 0Bpix|mq
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A: UNION 运算符 ;MR(Eaep
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。 RGim):1e
B: EXCEPT 运算符
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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。 jFBnP,WQ
C: INTERSECT 运算符 o!+jPwEU
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\wG3Oxol
注:使用运算词的几个查询结果行必须是一致的。 "xV9$m>
12、说明:使用外连接 "ujt:4p@
A、left outer join: |F 18j9
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 )cy_d!
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }Myi0I<
B:right outer join: )0:@T)G
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 A;A>Q`JJF
C:full outer join: to
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 'j+J?Y^
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二、提升 :!f1|h
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) OW12m{
法一:select * into b from a where 1<>1 A,T3%TE
法二:select top 0 * into b from a Sgt@G=_o
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &<P!o_+eb
insert into b(a, b, c) select d,e,f from b; ?*Kewj
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) #'-L`])7uw
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 v5 yOh5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. u&>o1!c*P
4、说明:子查询(表名1:a 表名2:b) huau(s0um
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ^r<bi%@C$
5、说明:显示文章、提交人和最后回复时间 rtz%(4aS
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `" E |
6、说明:外连接查询(表名1:a 表名2:b) F_$ K+6
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&L`C|0
7、说明:在线视图查询(表名1:a ) 8L?35[]e
select * from (SELECT a,b,c FROM a) T where t.a > 1; ? 1g<] ?
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 R9->.eE
select * from table1 where time between time1 and time2 j/R
select a,b,c, from table1 where a not between 数值1 and 数值2 .TURS
9、说明:in 的使用方法 ;TK:D=p4
select * from table1 where a [not] in ('值1','值2','值4','值6') av1*i3
10、说明:两张关联表,删除主表中已经在副表中没有的信息 dfo{ B/+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;q&>cnLDR
11、说明:四表联查问题: b7/1]
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 ..... Y24:D7Q
12、说明:日程安排提前五分钟提醒 :LL>C)(f
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 vTD`Ja#h
13、说明:一条sql 语句搞定数据库分页 ^zv28Wq>
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 Pv`^#BX'
14、说明:前10条记录 a"{tq Nc
select top 10 * form table1 where 范围 ?hS n)
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.) ) tGC&l+?/
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) o(.
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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 JeJc(e
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?.:C+*+
17、说明:随机取出10条数据 bQ=R,
select top 10 * from tablename order by newid() 1_7}B4
18、说明:随机选择记录 ]OoqU-q
select newid() Aov=qLWJ
19、说明:删除重复记录 u8*Uia*vwH
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) t`DoTb4
20、说明:列出数据库里所有的表名 '(kySf[
select name from sysobjects where type='U' )ll`F7B-
21、说明:列出表里的所有的 h{]l?6`
select name from syscolumns where id=object_id('TableName') ti'a^(
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。 zb}:wUR
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 /0 ,#c2aq
显示结果: %/H
type vender pcs @fp(uu
电脑 A 1 bgd1j,PWbW
电脑 A 1 B_[^<2_
光盘 B 2 5w`v
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光盘 A 2 !V.'~xj
手机 B 3 S)GWr"m-
手机 C 3 6ZVJ2xs[%
23、说明:初始化表table1 !9i,V{$c`"
TRUNCATE TABLE table1 JQ%`]=n(/
24、说明:选择从10到15的记录 iuq-M?1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Z^AACKME
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 ~?dPF;.6_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, aU2O5 z&
如: {vAq08
if @strWhere !='' EpeTfD
begin "j9,3yJT
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 38%]GQ
end s} ,p>8
else R\+p`n$
begin Nl7"|()e
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Fk>/
end
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我们可以直接写成 z@$7T:H>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere O'" &9
2、收缩数据库 |-I[{"6q$@
--重建索引
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DBCC REINDEX Tc@r#!.m
DBCC INDEXDEFRAG jjkiic+tDN
--收缩数据和日志 :a}hd^;[%8
DBCC SHRINKDB qU#Gz7/
DBCC SHRINKFILE q[l},nw
3、压缩数据库 &@A(8(%
dbcc shrinkdatabase(dbname) dapQ5JT/
4、转移数据库给新用户以已存在用户权限 {y'c*NS
exec sp_change_users_login 'update_one','newname','oldname' 8|?$KLz?F>
go G7`7e@{
5、检查备份集 A[Juv]X
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' p,@_A'
6、修复数据库 u
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ALTER DATABASE [dvbbs] SET SINGLE_USER rZ1${/6
GO iD_NpH q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK y`=A$>A
GO Y,B0=}
ALTER DATABASE [dvbbs] SET MULTI_USER ,'F;s:WM,
GO R1X9
7、日志清除 Jk|c!,!
SET NOCOUNT ON DVRE ;+Jt
DECLARE @LogicalFileName sysname, \A _g
@MaxMinutes INT, +is;$1rq
@NewSize INT cI'&gT5
USE tablename -- 要操作的数据库名 `R fhxzI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4W~pAruwr
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9rtcI[&?0
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9~<HTH
-- Setup / initialize O(h4;'/E
DECLARE @OriginalSize int "Sc_E}q|e
SELECT @OriginalSize = size Ta%{Wa\U9z
FROM sysfiles uE-~7Q(@
WHERE name = @LogicalFileName xRJv_=dT
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "Q#/J)N
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 'i{kuTv
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' d5%A64?
FROM sysfiles "MKgU[t
WHERE name = @LogicalFileName "o`N6@[w^
CREATE TABLE DummyTrans @X"p"3V
(DummyColumn char (8000) not null) a84^"GH7
DECLARE @Counter INT, l[l('-f
@StartTime DATETIME, SPeSe/
@TruncLog VARCHAR(255) ?z171X0
SELECT @StartTime = GETDATE(), GNqw]@'Yf
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ~9p*zC3M
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ytc
EXEC (@TruncLog) D&/(Avx.
-- Wrap the log if necessary. ^~0\d;l_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired v1QE|@
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) fnG&29x
AND (@OriginalSize * 8 /1024) > @NewSize UC;_}>
BEGIN -- Outer loop. b"t!nfgo
SELECT @Counter = 0 $VhUZGuG>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,;'9PsIS^
BEGIN -- update }?^5\ot u
INSERT DummyTrans VALUES ('Fill Log') R>To
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DELETE DummyTrans jtV{Lf3<
SELECT @Counter = @Counter + 1 j>+x|!k
END +T+f``RcK
EXEC (@TruncLog) =E8lpN'
END g9H~\w
SELECT 'Final Size of ' + db_name() + ' LOG is ' + vdYd~>w
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {%'(IJ|5z
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' B5IS-d
FROM sysfiles B8'" ^a^&-
WHERE name = @LogicalFileName i))S%!/r~
DROP TABLE DummyTrans cV_nYcLkz
SET NOCOUNT OFF C#`eN{%.YT
8、说明:更改某个表 uR|Jn)/m(
exec sp_changeobjectowner 'tablename','dbo' Y{B|*[xM
9、存储更改全部表 @O5-w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `ux
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@OldOwner as NVARCHAR(128), D:U:( pg
@NewOwner as NVARCHAR(128) 4T`u?T]
AS d Ayof=
DECLARE @Name as NVARCHAR(128) !1]72%k[
DECLARE @Owner as NVARCHAR(128) K~5QL/=1
DECLARE @OwnerName as NVARCHAR(128) p}hOkx4R\
DECLARE curObject CURSOR FOR 7KnZ
select 'Name' = name, cj`g)cX|
'Owner' = user_name(uid) :;t*:iG
from sysobjects ec[S?-
where user_name(uid)=@OldOwner !iWPldn&]
order by name j#"?Oe{_1
OPEN curObject t(-noy)
FETCH NEXT FROM curObject INTO @Name, @Owner GN /]^{D
WHILE(@@FETCH_STATUS=0) PCH&eTKN
BEGIN RRqHo~*0
if @Owner=@OldOwner qgvg
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begin L@2T
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }a,j1r_Hl&
exec sp_changeobjectowner @OwnerName, @NewOwner 5*xk8*
end xI55pj*
-- select @name,@NewOwner,@OldOwner (YF`#v6
FETCH NEXT FROM curObject INTO @Name, @Owner 'xm _oGWE
END SG2s!Ht
close curObject ~EG`[cv
deallocate curObject {O*WLZ {0
GO ]vMr@JM-G
10、SQL SERVER中直接循环写入数据 M%7{g"J*
declare @i int 9Ruj_U
set @i=1 ;"hED:z6%
while @i<30 +u#;k!B/>
begin ,OsFv}v7
insert into test (userid) values(@i) Eg-3GkC
set @i=@i+1 B\wH`5/KW
end 7c1xB.g
小记存储过程中经常用到的本周,本月,本年函数 Gy
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Dateadd(wk,datediff(wk,0,getdate()),-1) r`pg`ChHv
Dateadd(wk,datediff(wk,0,getdate()),6) %<CahzYc6
Dateadd(mm,datediff(mm,0,getdate()),0) Wp`wIe6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Dj'aWyW'
Dateadd(yy,datediff(yy,0,getdate()),0) jxU1u"WU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %Wkvo-rOq
上面的SQL代码只是一个时间段 ;t{Ew+s
Dateadd(wk,datediff(wk,0,getdate()),-1) dFFJw[$8w
Dateadd(wk,datediff(wk,0,getdate()),6) nR-`;lrF~
就是表示本周时间段. Mdsn"Y V
下面的SQL的条件部分,就是查询时间段在本周范围内的: MU4/arXy
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (|I:d!>:U
而在存储过程中 "ys#%,Z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Xi^3o
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Q3vC^}Dmr