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。 =R*qP ;#
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一、基础 P"B0_EuR<T
1、说明:创建数据库 ):i&`}SY
CREATE DATABASE database-name <Utnz)
2、说明:删除数据库 ~HOy:1QhE=
drop database dbname q#<^ ^4U
3、说明:备份sql server 0 stc9_O
--- 创建 备份数据的 device 9E>xIJ@J2T
USE master |B?27PD
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Re P|UH
--- 开始 备份 X!e[GJ
BACKUP DATABASE pubs TO testBack $5Xh,DOg
4、说明:创建新表 6d_'4B
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) yzqVz_Fi*W
根据已有的表创建新表: H&:jcgV*P
A:create table tab_new like tab_old (使用旧表创建新表) U2bjFLd"
B:create table tab_new as select col1,col2... from tab_old definition only su*'d:L
5、说明:删除新表 %Ev4]}2C1
drop table tabname tmQH|'>>
6、说明:增加一个列 0NS<?p~_S
Alter table tabname add column col type /YZr~|65
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 E\Rhz]G(
7、说明:添加主键: Alter table tabname add primary key(col) x>Zn?YR,"
说明:删除主键: Alter table tabname drop primary key(col) b )B?
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8、说明:创建索引:create [unique] index idxname on tabname(col....) {q"OM*L(
删除索引:drop index idxname "?V0$-DR
注:索引是不可更改的,想更改必须删除重新建。 i_j[?.?X}
9、说明:创建视图:create view viewname as select statement &YF^j2
删除视图:drop view viewname &*+'>UEe5
10、说明:几个简单的基本的sql语句 "rx-_uK*
选择:select * from table1 where 范围 C?lcGt!H
插入:insert into table1(field1,field2) values(value1,value2) mV3cp rRqv
删除:delete from table1 where 范围 O8h%3&
更新:update table1 set field1=value1 where 范围 V5UF3'3;}
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! eEuvl`&
排序:select * from table1 order by field1,field2 [desc] Vh_P/C+
总数:select count as totalcount from table1 i\,-oO
求和:select sum(field1) as sumvalue from table1 7Zlw^'q$:L
平均:select avg(field1) as avgvalue from table1 M7pOLP_1jB
最大:select max(field1) as maxvalue from table1 WA+iYLx@H
最小:select min(field1) as minvalue from table1 u6AA4(
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11、说明:几个高级查询运算词 7pe\M/kl
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A: UNION 运算符 gt@m?w(
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 -*1J f&
B: EXCEPT 运算符 #qK:J;Sn3
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 |y(Q
C: INTERSECT 运算符 f&Gt|
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 }H^+A77v
注:使用运算词的几个查询结果行必须是一致的。 )h7<?@wv&
12、说明:使用外连接 e )d`pQ6
A、left outer join: <J)]mh dm
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 '@_d(N1jTw
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |olA9mp|]
B:right outer join: nAv#?1cjz
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 aDU<wxnSvO
C:full outer join: k$blEa4
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。 Ff)8Q.m
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二、提升 A1O'|7X
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Sc;BCl{=|
法一:select * into b from a where 1<>1 4K\G16'$v
法二:select top 0 * into b from a 8Vr%n2M
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) pH9VTM.*
insert into b(a, b, c) select d,e,f from b; l3)}qu
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) 4h|c<-`>t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k>;`FFQU>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. HiZ*+T.B
4、说明:子查询(表名1:a 表名2:b) G?O1>?4C
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) 6^]+[q}3
5、说明:显示文章、提交人和最后回复时间 !|^|,"A)
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b T&6l$1J
6、说明:外连接查询(表名1:a 表名2:b) 8A##\j)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c vS;RJg=
7、说明:在线视图查询(表名1:a ) %)1y AdG
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select * from (SELECT a,b,c FROM a) T where t.a > 1; CsGx@\jN
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 >;e~ WF>+K
select * from table1 where time between time1 and time2 Kp%2k^U
select a,b,c, from table1 where a not between 数值1 and 数值2 C5o#i*|
9、说明:in 的使用方法 >qnko9 V
select * from table1 where a [not] in ('值1','值2','值4','值6') Va"0>KX
10、说明:两张关联表,删除主表中已经在副表中没有的信息 <^#,_o,!
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;U/&I3dzV
11、说明:四表联查问题: ag [ZW
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... */`ki;\A
12、说明:日程安排提前五分钟提醒 t}r' k/[
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 01t1Z}!y
13、说明:一条sql 语句搞定数据库分页 ^aItoJq
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 0"<H;7K#W
14、说明:前10条记录 V?6a8lJ
select top 10 * form table1 where 范围 ZMQZs~;~d
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ,Vc6Gwm
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) wr$("A(
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 rV ` #[d
(select a from tableA ) except (select a from tableB) except (select a from tableC) J,'M4O\S
17、说明:随机取出10条数据 SW@$ci
select top 10 * from tablename order by newid() , qMzWa
18、说明:随机选择记录 fK>L!=Q
select newid() 1m4$ p2j
19、说明:删除重复记录 ~!B\(@GU
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) n(1l}TJy
20、说明:列出数据库里所有的表名 -*1d!
select name from sysobjects where type='U' f,U.7E
21、说明:列出表里的所有的 ?gA 8x
select name from syscolumns where id=object_id('TableName') )|ju~qbf
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。 P)Jgs
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 L+b6!2O,
显示结果: $*^7iT4q_t
type vender pcs V(H1q`ao9
电脑 A 1 BtkOnbz8X
电脑 A 1 Ua:}V n&!
光盘 B 2 B6MB48#0gs
光盘 A 2 |mZxfI
手机 B 3 Ytn9B}%o
手机 C 3 KI"#f$2&
23、说明:初始化表table1 .]8ZwAs=&
TRUNCATE TABLE table1 l{*@v=b(
24、说明:选择从10到15的记录 c[0}AGJ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc wON!MhA;
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三、技巧 {&&z-^
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?g_3 [Fk
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W: z6Koc0
如: 'TTLo|@"-
if @strWhere !='' \j$&DCv
begin G<L;4nA)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere yuh *
end s:n6rG
else S\CCrje
begin ?qb}?&1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' (d(CT;
end /2&c$9=1
我们可以直接写成 LQ@"Xe]5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere u+9hL4
2、收缩数据库 6fkRrD
--重建索引 0CHH)Bku
DBCC REINDEX 5?f ^Rz
DBCC INDEXDEFRAG Akq2 d;
--收缩数据和日志 Z%gh3
DBCC SHRINKDB /!0={G
DBCC SHRINKFILE =>m<GvQz
3、压缩数据库 {a =#B)6
dbcc shrinkdatabase(dbname) W_JlOc!y
4、转移数据库给新用户以已存在用户权限 ld[I}88$
exec sp_change_users_login 'update_one','newname','oldname' tR#OjkvX
go sU=H&D99
5、检查备份集 &sl0W-;0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' j`EXlc~
6、修复数据库 ))qy;Q,
ALTER DATABASE [dvbbs] SET SINGLE_USER x`mG<Yt
GO x'8x
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK p'Y^X
GO })'B<vq
ALTER DATABASE [dvbbs] SET MULTI_USER 'lH|eU&-
GO Ugr!"Q#M
7、日志清除 %aP!hy
SET NOCOUNT ON 0-B5`=yU
DECLARE @LogicalFileName sysname, XgZD%7
@MaxMinutes INT, 4j*
@NewSize INT &5>Kl}7
USE tablename -- 要操作的数据库名 !hm]fh_j
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 y#`tgJ:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. :a!^
@NewSize = 1 -- 你想设定的日志文件的大小(M) T; 4NRC
-- Setup / initialize P?%s
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DECLARE @OriginalSize int +5)nk}
SELECT @OriginalSize = size xw.A #Zb\_
FROM sysfiles |NlO7aQ>2H
WHERE name = @LogicalFileName ~?l |
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + zOJ%}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1v y*{D
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \<bx[,?
FROM sysfiles ."g`3tVK
WHERE name = @LogicalFileName B.=FSow
CREATE TABLE DummyTrans [:dY0r+
(DummyColumn char (8000) not null) pd?Mf=>#
DECLARE @Counter INT, G0Iw-vf
@StartTime DATETIME, M*0]ai|;
@TruncLog VARCHAR(255) [DuttFX^x
SELECT @StartTime = GETDATE(), :'Vf
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' )705V|v
DBCC SHRINKFILE (@LogicalFileName, @NewSize) TP*hd
EXEC (@TruncLog) vz&|J
-- Wrap the log if necessary. 7P} W
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9i:L&dN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 5=-Q4d
AND (@OriginalSize * 8 /1024) > @NewSize yNPVOp*
BEGIN -- Outer loop. IW5,7.
SELECT @Counter = 0 e1yt9@k,
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `>o{P/HN
BEGIN -- update nkPh,X\N0
INSERT DummyTrans VALUES ('Fill Log') =F|{#F
DELETE DummyTrans /'SNw?&
SELECT @Counter = @Counter + 1 R*,MfV
END @NR>{Eg
EXEC (@TruncLog) .'6gZKXY
END 7g^]:3f!
SELECT 'Final Size of ' + db_name() + ' LOG is ' + XPc^Tq
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [NTzcSN.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' &$+AXzn
FROM sysfiles ,~U>'&M;
WHERE name = @LogicalFileName JtE M,tK
DROP TABLE DummyTrans G/E+L-N#`
SET NOCOUNT OFF {p2!|A&a
8、说明:更改某个表 l$KA)xbI
exec sp_changeobjectowner 'tablename','dbo' t9lPb_70
9、存储更改全部表 j^*dmX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch <sbu;dQ`
@OldOwner as NVARCHAR(128), )$2QZ
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@NewOwner as NVARCHAR(128) HZE#Ab*L
AS }FROB/
DECLARE @Name as NVARCHAR(128) =IZT(8
DECLARE @Owner as NVARCHAR(128) L(6d&t'|-R
DECLARE @OwnerName as NVARCHAR(128) 'ms-*c&
DECLARE curObject CURSOR FOR C[cbbp
select 'Name' = name, `7E;VL^Y1
'Owner' = user_name(uid) u,ho7ht3(
from sysobjects [(i
where user_name(uid)=@OldOwner ~ah~cwmpS
order by name B`)BZ,#p
OPEN curObject |d2SIyUc
FETCH NEXT FROM curObject INTO @Name, @Owner (TtkFo'!U
WHILE(@@FETCH_STATUS=0) NWESP U):w
BEGIN /8'NG6"H`
if @Owner=@OldOwner
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begin c^xIm'eob
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,L2ZinU:
exec sp_changeobjectowner @OwnerName, @NewOwner P8:dU(nlW
end |l^uEtG
-- select @name,@NewOwner,@OldOwner >b}o~F^J
FETCH NEXT FROM curObject INTO @Name, @Owner 8Al{+gx@?
END 8
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close curObject g/d<Zfq<{
deallocate curObject 4i;{!sT
GO ,<_A2t 2
10、SQL SERVER中直接循环写入数据 b~P`qj[
declare @i int eS^7A}*wd-
set @i=1 9.M4o[
while @i<30 n+9=1Oo"
begin *8 A
insert into test (userid) values(@i) h+H%?:FX
set @i=@i+1 >h9IM$2
end J1U/.`Oy
小记存储过程中经常用到的本周,本月,本年函数 )r?}P1J7
Dateadd(wk,datediff(wk,0,getdate()),-1) KZY}%il!`
Dateadd(wk,datediff(wk,0,getdate()),6) _yx>TE2e
Dateadd(mm,datediff(mm,0,getdate()),0) VT)oLj/A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \.{$11P#
Dateadd(yy,datediff(yy,0,getdate()),0) D/gw .XYL
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .hb:s,0mP
上面的SQL代码只是一个时间段 3pROf#M
Dateadd(wk,datediff(wk,0,getdate()),-1) C
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Dateadd(wk,datediff(wk,0,getdate()),6) Qy<P463A(l
就是表示本周时间段. wU36sCo
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~vhE|f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Q$W
而在存储过程中 O:R*rJ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 2 a)xTA#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) s\(k<Ks