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。 d5%A64?
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一、基础 $k V^[
1、说明:创建数据库 }f<.07
CREATE DATABASE database-name "N"9PTX
2、说明:删除数据库 ]0zXpMNI
drop database dbname ?z171X0
3、说明:备份sql server GNqw]@'Yf
--- 创建 备份数据的 device U"A]b(54
USE master 'AE)&56
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %:N6#;l M
--- 开始 备份 vN-#Ej.
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BACKUP DATABASE pubs TO testBack Zk)]=<H
4、说明:创建新表 Lc f =)GL
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1[a;2xA~
根据已有的表创建新表: $&='&q
A:create table tab_new like tab_old (使用旧表创建新表) $VhUZGuG>
B:create table tab_new as select col1,col2... from tab_old definition only ,;'9PsIS^
5、说明:删除新表 v}IkY
drop table tabname R>To
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6、说明:增加一个列 jtV{Lf3<
Alter table tabname add column col type j>+x|!k
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 +T+f``RcK
7、说明:添加主键: Alter table tabname add primary key(col) Z[yQKy
说明:删除主键: Alter table tabname drop primary key(col) pN&5vu30
8、说明:创建索引:create [unique] index idxname on tabname(col....) Ix^xL+Tm
删除索引:drop index idxname N't*e Ci
注:索引是不可更改的,想更改必须删除重新建。 kz(%8qi8&
9、说明:创建视图:create view viewname as select statement S`BLwnU`#
删除视图:drop view viewname +eZR._&0
10、说明:几个简单的基本的sql语句 9l@VxX68M
选择:select * from table1 where 范围 `)&-;CMY
插入:insert into table1(field1,field2) values(value1,value2) ?0WJB[/
删除:delete from table1 where 范围 <bWhTNOb
更新:update table1 set field1=value1 where 范围 Q_euNoA0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! vAbMU
排序:select * from table1 order by field1,field2 [desc] ZTWbe
总数:select count as totalcount from table1 ;M{ @23?`
求和:select sum(field1) as sumvalue from table1 :kfHILi
平均:select avg(field1) as avgvalue from table1 X5cl'J(j9
最大:select max(field1) as maxvalue from table1 bBc<yaN
最小:select min(field1) as minvalue from table1 0R>M_|
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11、说明:几个高级查询运算词 `$jc=ZLm
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A: UNION 运算符 cXFNX<
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。 0
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B: EXCEPT 运算符 &7!&]kA+
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。 Gmi4ffIb3
C: INTERSECT 运算符 ``)ys^V
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。 j8$*$|
注:使用运算词的几个查询结果行必须是一致的。 $U<so{xn%
12、说明:使用外连接 b-'41d}Hn
A、left outer join: R)"Ds}1G
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。 znw\Dn?g
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 @Nn9-#iW
B:right outer join: Pdmfn8I]%
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。 E'?yI'~=
C:full outer join: 9w^1/t&=04
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。 $(H%|Oyn
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二、提升 mVg-z~44T
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <LIL{g0eX
法一:select * into b from a where 1<>1 UJ1iXV[h"
法二:select top 0 * into b from a BK]bSj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) n$g g$<
insert into b(a, b, c) select d,e,f from b; DnS#
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) F=U3o=-:
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &*B=5W;6^u
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 2--"@@
4、说明:子查询(表名1:a 表名2:b) 3k py3z[%
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) jxU1u"WU
5、说明:显示文章、提交人和最后回复时间 %Wkvo-rOq
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b R"EX$Zj^E
6、说明:外连接查询(表名1:a 表名2:b) $-[V)]h
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Q<3=s6@T
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; @tWyc%t
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 cJd~UQ<k
select * from table1 where time between time1 and time2 t8DySFT
select a,b,c, from table1 where a not between 数值1 and 数值2 rn #FmM
9、说明:in 的使用方法 :3M2zV
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select * from table1 where a [not] in ('值1','值2','值4','值6') Q3vC^}Dmr
10、说明:两张关联表,删除主表中已经在副表中没有的信息 uV!Ax*'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) L}*:,&Y/
11、说明:四表联查问题: {O9CYP:
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 ..... [x
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12、说明:日程安排提前五分钟提醒 `=g9Rg/<
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wN\%b}pp
13、说明:一条sql 语句搞定数据库分页 o@mZ 6!ax3
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 K9B_o,
14、说明:前10条记录 k3h,c;
select top 10 * form table1 where 范围 l5F>v!NA
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.) D]S@U>]M!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _]a8lr+_-
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 ;,![Lar5L
(select a from tableA ) except (select a from tableB) except (select a from tableC) "Lk-R5iFd
17、说明:随机取出10条数据 @.;] $N&J
select top 10 * from tablename order by newid() ,)e&u1'
18、说明:随机选择记录 (lq7 ct
select newid() fCdd,,,}
19、说明:删除重复记录 Kq
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) r!N)pt<g
20、说明:列出数据库里所有的表名 &^3KF0\Q
select name from sysobjects where type='U' o^hI\9
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') h@}KBK
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 {"$
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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 y! he<4
显示结果: r|wB&
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type vender pcs P,r9<
电脑 A 1 y|f`sBMM
电脑 A 1 aG.j0`)%
光盘 B 2 PXqLK3AE
光盘 A 2 3^AycwNBA
手机 B 3 eL3HX _2(
手机 C 3 GO{o #}
23、说明:初始化表table1 2?9 FFlX
TRUNCATE TABLE table1 0g}+%5]yg
24、说明:选择从10到15的记录 64;F g/t
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L1A0->t
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三、技巧 GxE"q-G
1、1=1,1=2的使用,在SQL语句组合时用的较多 J0CEZ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @ FVan
如: ~WXT0-,
if @strWhere !='' FjF:Eh
begin #va|&QBZxM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 35I y\
end rq bX9M^
else _9!*laR!2
begin 8 #fzL7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' p?(w! O
end Y^80@MJ
我们可以直接写成 hT4u;3xE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere t)P5bQ+$u9
2、收缩数据库 7Gb1[3
--重建索引
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DBCC REINDEX D-\WS^#
DBCC INDEXDEFRAG M:x?I_JG8
--收缩数据和日志 u&/[sqx
DBCC SHRINKDB 'zCJK~x`x
DBCC SHRINKFILE r2A%.bL#
3、压缩数据库 ,CqJ((
dbcc shrinkdatabase(dbname) 37GJ}%Qs
4、转移数据库给新用户以已存在用户权限 !T;*F%G9
exec sp_change_users_login 'update_one','newname','oldname' 1-[~}
go gM_z`H5[!
5、检查备份集 "Y0:Y?Vz"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *)0bifw$&
6、修复数据库 c@9jc^CJ
ALTER DATABASE [dvbbs] SET SINGLE_USER "^E/N},%u5
GO PhBdm'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK }%(e`[?1
GO 7L~LpB
ALTER DATABASE [dvbbs] SET MULTI_USER EH))%LY1y
GO > w:+nG/r
7、日志清除 fDyFkhc
SET NOCOUNT ON bl@0+NiM
DECLARE @LogicalFileName sysname, #U45H.Rz
@MaxMinutes INT, @V{s'V
@NewSize INT
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USE tablename -- 要操作的数据库名 Y@x }b{3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 jO
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. n5CjwLgu\b
@NewSize = 1 -- 你想设定的日志文件的大小(M) MG ,exN
@
-- Setup / initialize i'&KoR?
DECLARE @OriginalSize int KWtLrZ(j
SELECT @OriginalSize = size Hik8u!#P
FROM sysfiles <[{Ty+
WHERE name = @LogicalFileName BG:l Zj'I
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3`sM/BoA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + F02S(WWo;
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' b]S4\BBT
FROM sysfiles .b]
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WHERE name = @LogicalFileName xbJ@ z{
CREATE TABLE DummyTrans Wy^43g38'p
(DummyColumn char (8000) not null) w5*?P4P
DECLARE @Counter INT, P<P4*cOV
@StartTime DATETIME, )zw}+z3st
@TruncLog VARCHAR(255) ,Q|[Yr
SELECT @StartTime = GETDATE(), ]~S,K}T
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' }p-<+sFo
DBCC SHRINKFILE (@LogicalFileName, @NewSize) mXZOkx{
EXEC (@TruncLog) C =fs[
-- Wrap the log if necessary. Y4*ezt:;Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tI50z khaB
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) r,}U-S.w
AND (@OriginalSize * 8 /1024) > @NewSize ! K? o H
BEGIN -- Outer loop. 9>~UqP9
SELECT @Counter = 0 T&Dt;CSF
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) dm3cQ<0
BEGIN -- update ^]mwL)I}
INSERT DummyTrans VALUES ('Fill Log') tln*Baq
DELETE DummyTrans T' O5>e
SELECT @Counter = @Counter + 1 OiPE,sv
END RqTW$94RD
EXEC (@TruncLog) Q*wub9
END "=)i'x"0"
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :$Lu
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _r!''@B
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' o6f^DG3*
FROM sysfiles ]{0R0Gr94
WHERE name = @LogicalFileName 0Yz
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DROP TABLE DummyTrans {l&6=z
SET NOCOUNT OFF N<wy"N{iS
8、说明:更改某个表 zt/p'khP3
exec sp_changeobjectowner 'tablename','dbo' gb
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9、存储更改全部表 #6g-{OBv
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch :`BZ,j_
@OldOwner as NVARCHAR(128), b_88o-*/
@NewOwner as NVARCHAR(128) Kj[X1X5
AS &.k'Dj2hf
DECLARE @Name as NVARCHAR(128) l:NEK`>i
DECLARE @Owner as NVARCHAR(128) (WT0j
DECLARE @OwnerName as NVARCHAR(128) }W&hPC
DECLARE curObject CURSOR FOR S.o 9AUv9
select 'Name' = name, v=Ep
'Owner' = user_name(uid) aYQ!`mS::M
from sysobjects v5"5UPi-
where user_name(uid)=@OldOwner X\3IY:Q@T
order by name _Y@'<S.
OPEN curObject ;u;Y fOr
FETCH NEXT FROM curObject INTO @Name, @Owner >L$g ;(g
WHILE(@@FETCH_STATUS=0) n"B"Aysz
BEGIN J;+AG^U<
if @Owner=@OldOwner TbyQ'MbUv
begin SF*!Z2K
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ahgm*Cpc
exec sp_changeobjectowner @OwnerName, @NewOwner cy=,Dr9O
end $q#|B3N%
-- select @name,@NewOwner,@OldOwner v8!
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FETCH NEXT FROM curObject INTO @Name, @Owner M7vc/E}]n
END }N;c
close curObject :32
deallocate curObject ?8wFT!J
GO (:3rANY|
10、SQL SERVER中直接循环写入数据 ':yE5j
declare @i int Zyqh
set @i=1 vPuPSE%M
while @i<30 xM85^B'
begin ?! dp0<
insert into test (userid) values(@i) @Tmqw(n{
set @i=@i+1 Nt42v
end *LJN2;
小记存储过程中经常用到的本周,本月,本年函数 s+?r4t3H!
Dateadd(wk,datediff(wk,0,getdate()),-1) pE >~F
Dateadd(wk,datediff(wk,0,getdate()),6) U+sAEN_e k
Dateadd(mm,datediff(mm,0,getdate()),0) T1m097
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !Dp4uE:Pq
Dateadd(yy,datediff(yy,0,getdate()),0) DmAMr=p
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) btb-MSkO
上面的SQL代码只是一个时间段 V.J[Uwf
Dateadd(wk,datediff(wk,0,getdate()),-1) d#7 z
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Dateadd(wk,datediff(wk,0,getdate()),6) MNip;S_j
就是表示本周时间段. i}Ea>bi{N
下面的SQL的条件部分,就是查询时间段在本周范围内的: %)_R>. >
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Pz3jc|Ga
而在存储过程中 mMO:m8W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _QCspPT' c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ,vP9oY[n