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。 bMA0#e2
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一、基础 s||c#+j"8
1、说明:创建数据库 +=`*`eP:U
CREATE DATABASE database-name | |u
2、说明:删除数据库 %p(X*mVX
drop database dbname [Ot<8)Jm
3、说明:备份sql server 1`sTGNo
--- 创建 备份数据的 device {/|tVc63
USE master "C.cU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' XxY wBc'pc
--- 开始 备份 *`_2uBz
BACKUP DATABASE pubs TO testBack cGSG}m@B`
4、说明:创建新表 TFNB%|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) uhm3}mWv
根据已有的表创建新表: <^w4+5sT/
A:create table tab_new like tab_old (使用旧表创建新表) qoP/`Y6
B:create table tab_new as select col1,col2... from tab_old definition only ATWa/"l(H-
5、说明:删除新表 1{<r~
drop table tabname Y<t(m$s
6、说明:增加一个列 #Ibpf ,
Alter table tabname add column col type o3X0c6uU
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^XHjQ
7、说明:添加主键: Alter table tabname add primary key(col) %,+&Kl
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说明:删除主键: Alter table tabname drop primary key(col) 7fC:'1]G
8、说明:创建索引:create [unique] index idxname on tabname(col....) eUKl(
删除索引:drop index idxname gle<{
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注:索引是不可更改的,想更改必须删除重新建。 %l3f .
9、说明:创建视图:create view viewname as select statement I_Omv{&u
删除视图:drop view viewname =PjxMC._
10、说明:几个简单的基本的sql语句 d/[kky}
选择:select * from table1 where 范围 } 4ZWAzH
插入:insert into table1(field1,field2) values(value1,value2) =u`tlN5pOT
删除:delete from table1 where 范围 A[`2Mnj
更新:update table1 set field1=value1 where 范围 oL7F^34;
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! IQWoK"B
排序:select * from table1 order by field1,field2 [desc] ]wUH*\(y
总数:select count as totalcount from table1 PVSz%"
求和:select sum(field1) as sumvalue from table1 :W9a t
平均:select avg(field1) as avgvalue from table1 6lL^/$]
最大:select max(field1) as maxvalue from table1 ddbQFAQQQ
最小:select min(field1) as minvalue from table1 IkG;j+=
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11、说明:几个高级查询运算词 oX'@,(6)
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A: UNION 运算符 \;!7IIe#
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 fn.;C
B: EXCEPT 运算符 fJ6Q:7
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 eKo=g|D
C: INTERSECT 运算符 ;*ni%|K
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 @1' Y/dCyD
注:使用运算词的几个查询结果行必须是一致的。 [=tIgMmz
12、说明:使用外连接 G}LV"0?
A、left outer join: C7f*Q[
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 id" l"
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c TAqX
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B:right outer join: TtH!5{$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。 >3~)2)Q
C:full outer join: gv D*^
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。 MOay^{u
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二、提升 iq^;c syKb
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) }Z t#OA
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法一:select * into b from a where 1<>1 #{^qBP[
法二:select top 0 * into b from a b'z\|jY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) YpRhl(|
insert into b(a, b, c) select d,e,f from b; A)Rh
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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) 3+vVdvu%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 bI_MF/r''
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]0[ot$Da6
4、说明:子查询(表名1:a 表名2:b) k#7A@Vb
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ]ms+Va_/
5、说明:显示文章、提交人和最后回复时间 ZU;jz[}
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [hk/Rp7{
6、说明:外连接查询(表名1:a 表名2:b) F?0Q AA
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c y~\uS
7、说明:在线视图查询(表名1:a ) ,A)Z.OWOq
select * from (SELECT a,b,c FROM a) T where t.a > 1; k g Rys
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 0&b;!N!vJ
select * from table1 where time between time1 and time2 DL,]iJm
select a,b,c, from table1 where a not between 数值1 and 数值2 lC,~_Yb
9、说明:in 的使用方法 8G9( )UF.
select * from table1 where a [not] in ('值1','值2','值4','值6') l4(FM}0X5}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ;:+2.//
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) r y@p
11、说明:四表联查问题: zMBGpqdP
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... fny6`_O
12、说明:日程安排提前五分钟提醒 C5$?Y8B3
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 o;#8=q
13、说明:一条sql 语句搞定数据库分页 q">}3`k
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 R*XZPzg%
14、说明:前10条记录 qDz[=6BF
select top 10 * form table1 where 范围 =6i+K.}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.) [!8bjc]c
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) n2Mpo\2
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 \Sv|yQUT
(select a from tableA ) except (select a from tableB) except (select a from tableC) ccp9nXv
17、说明:随机取出10条数据 %+;l|Z{Uf
select top 10 * from tablename order by newid() ,8d&uR}x
18、说明:随机选择记录 rmtCCPF?0
select newid() gs0`nysM#
19、说明:删除重复记录 JG1q5j##]b
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f5l\3oL
20、说明:列出数据库里所有的表名 rc~)%M<[2
select name from sysobjects where type='U' 1$6
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21、说明:列出表里的所有的 mH5>50H;
select name from syscolumns where id=object_id('TableName') rKdsVW
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。 3>73s}3
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 sG[qlzR=8
显示结果: *yo'Nqu
type vender pcs ,:MUf]Ky
电脑 A 1 M"u=)CT
电脑 A 1 ITi#p%
光盘 B 2 `T ^0&#
光盘 A 2 ;C
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手机 B 3 ^P/OHuDL
手机 C 3 @ PhAg
23、说明:初始化表table1 e^\#DDm
TRUNCATE TABLE table1 @~N"MsF3
24、说明:选择从10到15的记录 @\xEK5 SG
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Cw kQhj?
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三、技巧 1&7?f
1、1=1,1=2的使用,在SQL语句组合时用的较多 CRrEs
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3webAaO
如: QR8]d1+GV
if @strWhere !='' 2Dvq3VbiO"
begin Us2> 5 :\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T2)CiR-b
end f;l}Z|dok6
else ) .' + {
begin B>\q!dX3
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' k]RQ 7e
end *-q&~
我们可以直接写成 ]gv3|W
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere D+ jvF
2、收缩数据库 Sz')1<
--重建索引 D;+Y0B
DBCC REINDEX R"CF xo
DBCC INDEXDEFRAG rwh4/h^S
--收缩数据和日志 [C~N#S[]
DBCC SHRINKDB XbFo#Pwk
DBCC SHRINKFILE 9(vp`Z8B4
3、压缩数据库 erTly2-SJ
dbcc shrinkdatabase(dbname) (I>S qM
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4、转移数据库给新用户以已存在用户权限 I|c?*~7*
exec sp_change_users_login 'update_one','newname','oldname' m6xbO
go hjk]?MC
5、检查备份集 n:s _2h(u
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' EqIs&){
6、修复数据库 00y(E@~
ALTER DATABASE [dvbbs] SET SINGLE_USER 6Iz!_
GO X(DP=C}v9
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK c5O8,sT
GO L5 Ai
ALTER DATABASE [dvbbs] SET MULTI_USER gf4Hq&Rf
GO d& v 7l
7、日志清除 $`t2SD
SET NOCOUNT ON h2:TbQ
DECLARE @LogicalFileName sysname, P# 8lO%;
@MaxMinutes INT, ,,#6SR(n
@NewSize INT a8k`Wog
USE tablename -- 要操作的数据库名 1}ifJ~)5S
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 O]F(vHK\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. CR#-!_=4
@NewSize = 1 -- 你想设定的日志文件的大小(M) ('d,Sh
-- Setup / initialize Cgf4E{\U!
DECLARE @OriginalSize int B/hQvA;(
SELECT @OriginalSize = size MD,BGO?C
FROM sysfiles i-dosY`81
WHERE name = @LogicalFileName >:FmAey
SELECT 'Original Size of ' + db_name() + ' LOG is ' + puEu)m^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "l#"c{ee{
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Lc-WfzT
FROM sysfiles nU#K=e
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WHERE name = @LogicalFileName G1ruF8
CREATE TABLE DummyTrans ]A l)>
(DummyColumn char (8000) not null) {\LLiU}MJC
DECLARE @Counter INT, ^ ~Tn[w W_
@StartTime DATETIME, Sb)}
@TruncLog VARCHAR(255) B LZ<"npn
SELECT @StartTime = GETDATE(), I;, n|o
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6D{70onY+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Uhyf
EXEC (@TruncLog) .&>3nu
-- Wrap the log if necessary. X1V~.kvt)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;~`/rh
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1$m{)Io2(
AND (@OriginalSize * 8 /1024) > @NewSize uOd1:\%*
BEGIN -- Outer loop. "`Xbi/i
SELECT @Counter = 0 F2)KAIl
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]{ch]m
BEGIN -- update N7X(gh2h
INSERT DummyTrans VALUES ('Fill Log') *r!qxiY=
r
DELETE DummyTrans y4&x`|tv
SELECT @Counter = @Counter + 1 'I r
END PklJU:Pu\U
EXEC (@TruncLog) M}=fdH
END 6_g6e2F
SELECT 'Final Size of ' + db_name() + ' LOG is ' + q+w] Xs;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4>Nig.#
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @TzUcE
FROM sysfiles 8'v:26
WHERE name = @LogicalFileName kmu7~&75
DROP TABLE DummyTrans =xb/zu(
SET NOCOUNT OFF Pb59RE:7V
8、说明:更改某个表 QG@Z%P~,E
exec sp_changeobjectowner 'tablename','dbo' IZd~Am3f
9、存储更改全部表 ,wyEo>>4)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch G('UF1F
@OldOwner as NVARCHAR(128), /}5)[9GC
@NewOwner as NVARCHAR(128) -KqMSf&9
AS ~ntDzF
DECLARE @Name as NVARCHAR(128) v sYbR3O
DECLARE @Owner as NVARCHAR(128) X7MA>j3m
DECLARE @OwnerName as NVARCHAR(128) B!)Tytm9u
DECLARE curObject CURSOR FOR /-=h|A#Kh
select 'Name' = name, ^Q!A4qOQ
'Owner' = user_name(uid) G12o?N0p
from sysobjects )cm^;(#pV
where user_name(uid)=@OldOwner jd}~#:FUr*
order by name #X?E#^6?E
OPEN curObject U1|{7.R
FETCH NEXT FROM curObject INTO @Name, @Owner 3i9~'j;F3
WHILE(@@FETCH_STATUS=0) r8o^8 .
BEGIN OgCNqW
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if @Owner=@OldOwner aZo>3z;
begin _) UnHp_^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) gaE8\JSr
exec sp_changeobjectowner @OwnerName, @NewOwner r[2*K 9
end R~RE21kAc
-- select @name,@NewOwner,@OldOwner iN5[x{^t
FETCH NEXT FROM curObject INTO @Name, @Owner }CrWmJu0
END +.xK`_[M
close curObject g$qM}#s0}
deallocate curObject f{{J_""?&
GO mCQ:<#
10、SQL SERVER中直接循环写入数据 ^ Qxv5HS2
declare @i int GB)< 5I
set @i=1 a!;#u8f
while @i<30 \[wbJ
begin 1_M}Dc+J
insert into test (userid) values(@i) "Sw raq
set @i=@i+1 Mh@n>+IR
end _93:_L
小记存储过程中经常用到的本周,本月,本年函数 9)4_@rf%
Dateadd(wk,datediff(wk,0,getdate()),-1) @r\{iSg&g.
Dateadd(wk,datediff(wk,0,getdate()),6) ?5j~"
Dateadd(mm,datediff(mm,0,getdate()),0) ,!P}Y[|
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) U/h@Q\~U
Dateadd(yy,datediff(yy,0,getdate()),0) *lQa^F
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1L=)93,M
上面的SQL代码只是一个时间段 ^szi[Cj
Dateadd(wk,datediff(wk,0,getdate()),-1) | S'mF6Y
Dateadd(wk,datediff(wk,0,getdate()),6) X-psao0tI`
就是表示本周时间段. @H}Hjg_>m
下面的SQL的条件部分,就是查询时间段在本周范围内的: U+!&~C^y
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8wn{W_5a
而在存储过程中 BW"24JhF"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `dRqheX
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6wZ)GLW[