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>d_a;pX
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一、基础 >Jl(9)e
1、说明:创建数据库 X
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CREATE DATABASE database-name *Txt`z[|
2、说明:删除数据库 `wJR^O!e
drop database dbname bp06xHMu
3、说明:备份sql server ,DN>aEu1
--- 创建 备份数据的 device &*wN@e(c
USE master (RP"VEVR
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8._
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--- 开始 备份 *CHLs^)
BACKUP DATABASE pubs TO testBack K5O#BBX=
4、说明:创建新表 9'tElpDJ6#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) jt?937{
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) zj ;'0Zu
B:create table tab_new as select col1,col2... from tab_old definition only eIzT(3(
5、说明:删除新表 XwKB+Yj0
drop table tabname jl;%?bx
6、说明:增加一个列 l2)) StEm
Alter table tabname add column col type (x{6N^J.t
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。 ZGUhje!
7、说明:添加主键: Alter table tabname add primary key(col) j Y>BU&
说明:删除主键: Alter table tabname drop primary key(col) T}ZUw;}BL
8、说明:创建索引:create [unique] index idxname on tabname(col....) N`FgjnQ`
删除索引:drop index idxname rkF]Q_'`t;
注:索引是不可更改的,想更改必须删除重新建。 ;VY0DAp{
9、说明:创建视图:create view viewname as select statement l.ri]e
删除视图:drop view viewname Zrtyai{8l
10、说明:几个简单的基本的sql语句 p`@7hf|hm
选择:select * from table1 where 范围 (nWi9(}J
插入:insert into table1(field1,field2) values(value1,value2) 1(z&0Y ;
删除:delete from table1 where 范围 EgAM,\
更新:update table1 set field1=value1 where 范围 ,q F;#nB-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! a?4'',~
排序:select * from table1 order by field1,field2 [desc] N? r{Y$x
总数:select count as totalcount from table1 Byx8`Cx1
求和:select sum(field1) as sumvalue from table1 KLpe!8tAe
平均:select avg(field1) as avgvalue from table1 C
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最大:select max(field1) as maxvalue from table1 2f'3Vjp~G
最小:select min(field1) as minvalue from table1 0{0|M8
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11、说明:几个高级查询运算词 8lAs~c
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A: UNION 运算符 gxry?':
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Q;]g9T[)
B: EXCEPT 运算符 Xr54/.{&@
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 %d<uOCf\Q
C: INTERSECT 运算符 Q{ hXP*5
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 5$kv,%ah
注:使用运算词的几个查询结果行必须是一致的。 %#!pAUP\&
12、说明:使用外连接 `Zn2Vx
A、left outer join: NdpcfZq
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。 vYT%e:8)q
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 /s91[n(d
B:right outer join: .G"UM>.}d
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。 Rj&V~or
C:full outer join: mK!73<p_
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。 8Vcg30_+
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二、提升 >Qk4AMIO
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [i7Ug.Oi"
法一:select * into b from a where 1<>1 $O}:*.{(W
法二:select top 0 * into b from a 9EryHV|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) a@[y)xa$Z
insert into b(a, b, c) select d,e,f from b; Z:Hk'|q}I
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) ?NV3]vl
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {1H3VSYq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. gwvy$H
4、说明:子查询(表名1:a 表名2:b) J(CqT/Au-
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) *],]E;
5、说明:显示文章、提交人和最后回复时间 RS'%;B-)
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b o<\CA[
6、说明:外连接查询(表名1:a 表名2:b) l56D?E8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c yFp8 >
7、说明:在线视图查询(表名1:a ) X{SD3j=G#
select * from (SELECT a,b,c FROM a) T where t.a > 1; AL #w
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 `WDN T0@M
select * from table1 where time between time1 and time2 ^j1?L B
select a,b,c, from table1 where a not between 数值1 and 数值2 J%ym1A9
9、说明:in 的使用方法 bL`O k
select * from table1 where a [not] in ('值1','值2','值4','值6') ISy\g`d`C
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7r=BGoA2E
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) vM5u]u!
11、说明:四表联查问题: 'Wv=mBEfZ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... -\mbrbG9H
12、说明:日程安排提前五分钟提醒 52-Gk2dp
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 =;(w Bj
13、说明:一条sql 语句搞定数据库分页 Q_<CG[,6D1
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 j(Tt-a("z
14、说明:前10条记录 cnh\K.*}_x
select top 10 * form table1 where 范围 ]ee%=+'
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) )L?JH?$C
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) '2+Rb7V
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 1n7tmRl
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 q.L0rY!
select top 10 * from tablename order by newid() a%2r]:?^?
18、说明:随机选择记录 MH{$"^K
select newid() y>zPsc,
19、说明:删除重复记录 =k]Rze I
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) n,eO6X 4
20、说明:列出数据库里所有的表名 E]PHO\f-m}
select name from sysobjects where type='U' v%t "N
21、说明:列出表里的所有的 so h3d
select name from syscolumns where id=object_id('TableName') ?YR/'Vq97
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 |sWH!:]49
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type D@T>z;
显示结果: 1X\dH<B}
type vender pcs
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电脑 A 1 S[!-M\b
电脑 A 1 aagN-/mgm
光盘 B 2 XYD}OddO
光盘 A 2 V6'"J
手机 B 3 8/Z
手机 C 3 pQc5'*FKd
23、说明:初始化表table1 09y%FzV
TRUNCATE TABLE table1 E )D*~2o/
24、说明:选择从10到15的记录 3P C'P2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc r
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三、技巧 B5"(NJ;
1、1=1,1=2的使用,在SQL语句组合时用的较多 L{xCsJ3d
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Q:$<`K4)
如: Ij>IL!
if @strWhere !='' 4[t1"s~Wg
begin w[Ee#Yaj.-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *"#62U6
end ]c,ttS_
else +VSJve |
begin YX38*Ml+V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' D{YAEG
end /I|.^ Id|
我们可以直接写成 mZsftby}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere fMRBGcg7Dc
2、收缩数据库 *Q=ER
--重建索引 D. !m*oq
DBCC REINDEX 86!"b
DBCC INDEXDEFRAG C=L_@{^Rgb
--收缩数据和日志 INZycNqm,
DBCC SHRINKDB Z3E957}
DBCC SHRINKFILE iL f:an*vH
3、压缩数据库 '3B`4W,
dbcc shrinkdatabase(dbname) &!uw;|%
4、转移数据库给新用户以已存在用户权限 NQzpgf|h
exec sp_change_users_login 'update_one','newname','oldname' |5|^[v
go sU"D%G
5、检查备份集 "/6<k0.D&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' pE(\q+1<
6、修复数据库 j&n][=PL
ALTER DATABASE [dvbbs] SET SINGLE_USER cbvK;;
GO 't".~H_V
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK sdP% Y<eAT
GO EIO!f[]o
ALTER DATABASE [dvbbs] SET MULTI_USER F4+mkB:w*7
GO [9S\3&yoh
7、日志清除 6kH47Yc?
SET NOCOUNT ON !{5jP|vo
DECLARE @LogicalFileName sysname, 9An_zrJ%i
@MaxMinutes INT, udxLHs
@NewSize INT 1;E[Ml
USE tablename -- 要操作的数据库名 `M?C(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 q
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. P7r?rbO"
@NewSize = 1 -- 你想设定的日志文件的大小(M) n\k6UD
-- Setup / initialize Qd"{2>
DECLARE @OriginalSize int 3vTX2e.w
SELECT @OriginalSize = size LQ4GQqS*
FROM sysfiles 5Gm,lNQ Av
WHERE name = @LogicalFileName @=ABO"CQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + S^|Uzc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _urv
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' h_6QVab@
FROM sysfiles Di{T3~fqU
WHERE name = @LogicalFileName 6b+\2-eq
CREATE TABLE DummyTrans q)R&npP7
(DummyColumn char (8000) not null) |aef$f5
DECLARE @Counter INT, VQE8hQ37
@StartTime DATETIME, 'T@K$xL8
@TruncLog VARCHAR(255) wWm1G)
SELECT @StartTime = GETDATE(), `?VtB!p@x=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3XY;g{`=q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^6;n@
EXEC (@TruncLog) $(v1q[ig
-- Wrap the log if necessary. 5sui*WH
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired a>A29*q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) $7~k#_#PC
AND (@OriginalSize * 8 /1024) > @NewSize clK3kBh~&
BEGIN -- Outer loop. ,^,KWi9
SELECT @Counter = 0 ,aS6|~ac4
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9?B}CCE<LR
BEGIN -- update ? _36uJo}
INSERT DummyTrans VALUES ('Fill Log') WP&P#ju&
DELETE DummyTrans X8l[B{|
SELECT @Counter = @Counter + 1 QCkPua9
END e#0C
EXEC (@TruncLog) _YzItge*
END Q" BIk
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + QXx<Hi^ /
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + f ?:
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xZAc~~9tD
FROM sysfiles 6wH]W+A
WHERE name = @LogicalFileName K~gt=NH
DROP TABLE DummyTrans u
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SET NOCOUNT OFF Y$SZqW0!/
8、说明:更改某个表 jSVIO v:
exec sp_changeobjectowner 'tablename','dbo' -U;2
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9、存储更改全部表 0g% `L_e_
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch xI?%.Z;*+
@OldOwner as NVARCHAR(128), (Qmpz
@NewOwner as NVARCHAR(128) %rVC3}
AS u50 o1^<X
DECLARE @Name as NVARCHAR(128) zs!,PQF(
DECLARE @Owner as NVARCHAR(128) O'y8[<
DECLARE @OwnerName as NVARCHAR(128) zr%2oFeX,
DECLARE curObject CURSOR FOR d`9%:2qE
select 'Name' = name, ;w";s$
'Owner' = user_name(uid) Yt79W
from sysobjects igFz~
where user_name(uid)=@OldOwner <PL94
order by name U{(B)dFTH
OPEN curObject ) jBPt&
FETCH NEXT FROM curObject INTO @Name, @Owner t-_~jZ<
WHILE(@@FETCH_STATUS=0) _bB:1l?V
BEGIN -Z)j"J
if @Owner=@OldOwner RWM9cV5
begin GUyMo@g
set @OwnerName = @OldOwner + '.' + rtrim(@Name) SYkLia(Ty
exec sp_changeobjectowner @OwnerName, @NewOwner KS%LX c('
end O>UG[ZgW
-- select @name,@NewOwner,@OldOwner >jxo,xz
FETCH NEXT FROM curObject INTO @Name, @Owner %D|p7&
END TtA6N8G
close curObject T:$ a
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deallocate curObject J8Bz|.@Q
GO @jb
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10、SQL SERVER中直接循环写入数据 {&Kck>C'
declare @i int |HhqWja
set @i=1 feg
while @i<30 bHx09F]
begin :l~^un|<2Y
insert into test (userid) values(@i) qRk&b F/
set @i=@i+1 .}'49=c
end 1b*Me'
小记存储过程中经常用到的本周,本月,本年函数 )BI6nU
Dateadd(wk,datediff(wk,0,getdate()),-1) c:QZ(8d]L
Dateadd(wk,datediff(wk,0,getdate()),6) ^2C)Wk$
Dateadd(mm,datediff(mm,0,getdate()),0) 5[<"_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Mrpz (})
Dateadd(yy,datediff(yy,0,getdate()),0) \*] l'>x1
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9t)A_}O
上面的SQL代码只是一个时间段 dw'&Av'
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Dateadd(wk,datediff(wk,0,getdate()),-1) b
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Dateadd(wk,datediff(wk,0,getdate()),6) ?#N:
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就是表示本周时间段. 2% ],0,o
下面的SQL的条件部分,就是查询时间段在本周范围内的: k:1p:&*m
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) bYsK|n
而在存储过程中 5q<cZ)v#&
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S$O+p&!X
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Tp
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