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。 \n0gTwiO%
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一、基础 : bv|Ah
1、说明:创建数据库 Z| L2oce
CREATE DATABASE database-name /f&By
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2、说明:删除数据库 GP]TnQ<*;
drop database dbname a#QByP
3、说明:备份sql server `M rBav
--- 创建 备份数据的 device xid:" y=_&
USE master /q*KO\L
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' q^6N+ ^}QN
--- 开始 备份 b~as64
BACKUP DATABASE pubs TO testBack !KDr`CV&
4、说明:创建新表 u]*5Ex (?
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;eh/_hPM
根据已有的表创建新表: hVZo"XUb
A:create table tab_new like tab_old (使用旧表创建新表) !a[$)c
B:create table tab_new as select col1,col2... from tab_old definition only )*
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5、说明:删除新表 4NUNOv`[{
drop table tabname VN+\>j-
6、说明:增加一个列 k<Oy%+C
Alter table tabname add column col type 8^T2^gs
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。 5)*6V&
7、说明:添加主键: Alter table tabname add primary key(col) Ky6+~>
说明:删除主键: Alter table tabname drop primary key(col) D1ZC&B_}-
8、说明:创建索引:create [unique] index idxname on tabname(col....) f9F2U
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删除索引:drop index idxname YkI9d&ib+
注:索引是不可更改的,想更改必须删除重新建。 GBr,LN
9、说明:创建视图:create view viewname as select statement w"6aha* %7
删除视图:drop view viewname *;X-\6
10、说明:几个简单的基本的sql语句 qmID-t"
选择:select * from table1 where 范围 C9pnU,[
插入:insert into table1(field1,field2) values(value1,value2) >KHp-|0pv
删除:delete from table1 where 范围 en%B>]QI
更新:update table1 set field1=value1 where 范围 U2UyN9:6F
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1t#XQ?8
排序:select * from table1 order by field1,field2 [desc] B~rU1Y)
总数:select count as totalcount from table1 a7=YG6[
求和:select sum(field1) as sumvalue from table1 jYk5~<\k
平均:select avg(field1) as avgvalue from table1 ~4+8p9f
最大:select max(field1) as maxvalue from table1 ^k;mn-0
最小:select min(field1) as minvalue from table1 WP!il(Gr
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11、说明:几个高级查询运算词 `~h0?g
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A: UNION 运算符 GjL W`>
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。 d QDLI
B: EXCEPT 运算符 :fW.-^"VP
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。 &~}@u[=ux
C: INTERSECT 运算符 UI_v3c3b
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。 |C4o zl=O?
注:使用运算词的几个查询结果行必须是一致的。 :i}@Br+R7L
12、说明:使用外连接 Q2FQhc@L(:
A、left outer join: +8eVj#N
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。 SlT7L||Ww
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 ovSH}h!
B:right outer join: FF jRf
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。 N:7.:Yw
C:full outer join: k1m'Ka-
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。 YLE/w @*
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二、提升 oHk27U G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~\3l!zIq
法一:select * into b from a where 1<>1 h*l
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法二:select top 0 * into b from a w7r'SCVh3+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =CE HRny
insert into b(a, b, c) select d,e,f from b; CxkMhd8qz
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) ?o8a_9+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R7,pukK
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8a?IC|~Pz
4、说明:子查询(表名1:a 表名2:b) \Me"'.F?
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~|1kQ.
5、说明:显示文章、提交人和最后回复时间 -&$%|cyThQ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b k5q(7&C
6、说明:外连接查询(表名1:a 表名2:b) fH; |Rm
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !%X>rGkc
7、说明:在线视图查询(表名1:a ) $Q=$?>4U
select * from (SELECT a,b,c FROM a) T where t.a > 1; mcCB7<.
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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 8cB=}XgYS
select * from table1 where time between time1 and time2 eXc[3ceUr
select a,b,c, from table1 where a not between 数值1 and 数值2 M`(;>Kp7
9、说明:in 的使用方法 t Z+0}d
select * from table1 where a [not] in ('值1','值2','值4','值6') xS-w\vbLV
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ` 4OMZMq
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \6U 2-m'
11、说明:四表联查问题: @kS|Jz$iY
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 ..... N-Qu/,~+
12、说明:日程安排提前五分钟提醒 >}mNi:6xq
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wQ@Zwbx
13、说明:一条sql 语句搞定数据库分页 bKTqX[ =
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 y)0gJP
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14、说明:前10条记录 GpScc'a7
select top 10 * form table1 where 范围 $tEdBnf^ca
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) e<kpcF5{\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 hjw4Xzju
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,nI_8r"M>
17、说明:随机取出10条数据 uwmoM>I W^
select top 10 * from tablename order by newid() kBQ5]Q"
18、说明:随机选择记录 m9 ^m
select newid() 2-QuT"Gkd
19、说明:删除重复记录 7?+5%7-
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) g9M')8a n
20、说明:列出数据库里所有的表名 N|bPhssFw
select name from sysobjects where type='U' }klE0<W|5\
21、说明:列出表里的所有的 dBsRm{aS
select name from syscolumns where id=object_id('TableName') 2*N&q|ED
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Z3OZPxm
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type -/@|2!d
显示结果: zuK/(qZ
type vender pcs 9Ilfv
电脑 A 1 3csm`JVK
电脑 A 1 t`N
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光盘 B 2 wgC??Be;ut
光盘 A 2 #(m`2Z`H
手机 B 3 #FrwfJOV
手机 C 3 ^vYVl{$bT
23、说明:初始化表table1 x8\E~6`,
TRUNCATE TABLE table1 6 Xzk;p
24、说明:选择从10到15的记录 +s#S{b
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc em f0sL
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三、技巧 67Af} >Q
1、1=1,1=2的使用,在SQL语句组合时用的较多 } S'I
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ukk-(gjX
如: 2hjre3"?
if @strWhere !='' AAIyr703cQ
begin Y&ct+w]%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0"wbcAh)
end j1'xp`jgv
else L8,H9T#e
begin GC5#1+fQ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]# tGT0
end EM>c%BH<N
我们可以直接写成 [TiTff&LV
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rCnV5Yb0O
2、收缩数据库 ;o~+2Fir
--重建索引 7Va#{Y;Zy
DBCC REINDEX N}.Q%&6:
DBCC INDEXDEFRAG pq/FLYiv
--收缩数据和日志 Zi[{\7a
DBCC SHRINKDB lx A<iQia
DBCC SHRINKFILE g:~?U*f-
3、压缩数据库 (hRgYwUa<
dbcc shrinkdatabase(dbname) nzQYn
4、转移数据库给新用户以已存在用户权限 {2'74
exec sp_change_users_login 'update_one','newname','oldname' )7Ho n
go S<2CG)K[
5、检查备份集 1pYmtr
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' n)1
6、修复数据库 4 _c:Vl
ALTER DATABASE [dvbbs] SET SINGLE_USER Cn6n4, 0
GO 5'{qEZs^QU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK aPY>fy^8D
GO V,|Bzcz
ALTER DATABASE [dvbbs] SET MULTI_USER Mo/2,DiI5
GO &<fRej]v
7、日志清除 \gJapx(
SET NOCOUNT ON #+k.b_LS
DECLARE @LogicalFileName sysname, _x,-d|9bd
@MaxMinutes INT, $Z(g=nS>
@NewSize INT ,
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USE tablename -- 要操作的数据库名 <x>k3bD
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Im' :sJ31
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]"2 v7)e
@NewSize = 1 -- 你想设定的日志文件的大小(M) ga2Q3mV
-- Setup / initialize Z)6nu)
DECLARE @OriginalSize int j-C42Pfr
SELECT @OriginalSize = size W O+?gu
FROM sysfiles Z@c0(ol
WHERE name = @LogicalFileName @3expC
SELECT 'Original Size of ' + db_name() + ' LOG is ' + o?Tp=Ge
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \0^r J1*
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' G\,A> mT/P
FROM sysfiles H[_uVv;}6
WHERE name = @LogicalFileName q _T?G e
CREATE TABLE DummyTrans \{+nXn
(DummyColumn char (8000) not null) .1[2 CjQ
DECLARE @Counter INT, /F8\%l+
@StartTime DATETIME, dx?njR
@TruncLog VARCHAR(255) 0imqj7L
SELECT @StartTime = GETDATE(), VT.{[Kl
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' qeK
DBCC SHRINKFILE (@LogicalFileName, @NewSize) thZ@BrO#
EXEC (@TruncLog) 13_+$DhU-L
-- Wrap the log if necessary. F)<G]i8n~
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired OCOO02Wq1
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +k(3+b$S-
AND (@OriginalSize * 8 /1024) > @NewSize i6g[E4nk
BEGIN -- Outer loop. Cf1wM:K|8
SELECT @Counter = 0 I$6
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \Zz= 4
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BEGIN -- update {,-5k.P[
INSERT DummyTrans VALUES ('Fill Log') 7L~ zI>2
DELETE DummyTrans nGJIjo_I
SELECT @Counter = @Counter + 1 ,C'w(af@}
END )r6SGlE[Y
EXEC (@TruncLog) XpAq=p0;
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + '__3[D
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + IIt^e#s&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3RH#e1Y
FROM sysfiles
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WHERE name = @LogicalFileName ^p- e
DROP TABLE DummyTrans LOb'<R\p
SET NOCOUNT OFF m5;[,He
8、说明:更改某个表 tU2t oV
exec sp_changeobjectowner 'tablename','dbo' b=QGbFf
9、存储更改全部表 I }W-5%
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |`t!aG8
@OldOwner as NVARCHAR(128), k\thEEVP0*
@NewOwner as NVARCHAR(128) [sY1|eX
AS +@7x45;D
DECLARE @Name as NVARCHAR(128) C=_-p"O#
DECLARE @Owner as NVARCHAR(128) ~
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DECLARE @OwnerName as NVARCHAR(128) >La L!PnZ
DECLARE curObject CURSOR FOR 7pI\`*7b
select 'Name' = name, ~G^}2#5
'Owner' = user_name(uid) ;
# ?0#):-
from sysobjects =wR]X*Pan
where user_name(uid)=@OldOwner g(Xg%&@KZ
order by name 5iI3u 7Mn1
OPEN curObject Q3O .<9S
FETCH NEXT FROM curObject INTO @Name, @Owner 16> >4U:Y
WHILE(@@FETCH_STATUS=0) %WT:RT_
BEGIN >8fz ?A
if @Owner=@OldOwner |e[0Qo@
begin 2=,Sz1`t
set @OwnerName = @OldOwner + '.' + rtrim(@Name) gWv+i/,
exec sp_changeobjectowner @OwnerName, @NewOwner W*DIW;8p
end GxDF7
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-- select @name,@NewOwner,@OldOwner 8OtUY}R
FETCH NEXT FROM curObject INTO @Name, @Owner P$qkb|D,
END O2/w:zOg'
close curObject <C96]}/ ?
deallocate curObject /uz5V/i0
GO ?*mbce[
10、SQL SERVER中直接循环写入数据 KJJb^6P48W
declare @i int H|:)K^o
set @i=1 ?G>TaTiK#
while @i<30 `8.32@rUB.
begin PXu<4VF
insert into test (userid) values(@i) `FB?cPR
set @i=@i+1 yz$1qEII`q
end 5 /jY=/0.a
小记存储过程中经常用到的本周,本月,本年函数 |Ge/|;.v`
Dateadd(wk,datediff(wk,0,getdate()),-1) IS4K$Ac.
Dateadd(wk,datediff(wk,0,getdate()),6) g2>u]3&W
Dateadd(mm,datediff(mm,0,getdate()),0) Yg,lJ!q
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) r~fl=2>yQ
Dateadd(yy,datediff(yy,0,getdate()),0) 2:/MN2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Lz{T8yvZ
上面的SQL代码只是一个时间段 [,$mpJCI
Dateadd(wk,datediff(wk,0,getdate()),-1) S!!\!w>N
Dateadd(wk,datediff(wk,0,getdate()),6) .'mC3E+$
就是表示本周时间段. +siNU#!
下面的SQL的条件部分,就是查询时间段在本周范围内的: *]{I\rX
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) si.a]k/f
而在存储过程中 =LY^3TlDj
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ~)IJE+e>}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m1o65FsY08