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。 /CX VLl8~
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一、基础 /!&R9!6
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1、说明:创建数据库 ]]iPEm"@
CREATE DATABASE database-name WQePSU
2、说明:删除数据库 }iN2KeLAF
drop database dbname 9@VO+E$7L
3、说明:备份sql server 3.R#&Zxt
--- 创建 备份数据的 device _D!g4"
USE master ' [0AHM
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d]v+mVAyE
--- 开始 备份 /Wj,1WX~
BACKUP DATABASE pubs TO testBack m6n!rRQ^U
4、说明:创建新表 i76 Yo5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ?pGkk=,KB
根据已有的表创建新表: 3`V1XE.;
A:create table tab_new like tab_old (使用旧表创建新表) O/Y)&VG7
B:create table tab_new as select col1,col2... from tab_old definition only (M-ZQ
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5、说明:删除新表 z4U9n'{
drop table tabname %}Q&1P=
6、说明:增加一个列 }=}>9DSM
Alter table tabname add column col type b\55,La
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。 Jobiq]|>
7、说明:添加主键: Alter table tabname add primary key(col) L\aBc}
说明:删除主键: Alter table tabname drop primary key(col) v:_B kHN'
8、说明:创建索引:create [unique] index idxname on tabname(col....) l:(Rb-Wy
删除索引:drop index idxname iZ,YxN<R
注:索引是不可更改的,想更改必须删除重新建。 6tjcAsV
9、说明:创建视图:create view viewname as select statement :osz
删除视图:drop view viewname j .A6S`
10、说明:几个简单的基本的sql语句 p9ZXbAJ{
选择:select * from table1 where 范围 7S^""*Q^
插入:insert into table1(field1,field2) values(value1,value2) c'fSu;1
删除:delete from table1 where 范围 1&)_(|p[C
更新:update table1 set field1=value1 where 范围
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @1RP/y%
排序:select * from table1 order by field1,field2 [desc] l5t2\Fl
总数:select count as totalcount from table1 Ss?CfRM
求和:select sum(field1) as sumvalue from table1 :VA.Q rKW
平均:select avg(field1) as avgvalue from table1 u' Qd,
最大:select max(field1) as maxvalue from table1 B5am1y{P#
最小:select min(field1) as minvalue from table1 '_0]vupvY
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11、说明:几个高级查询运算词 JqU ADm
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A: UNION 运算符 alFjc.~}
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。 c@m5~
B: EXCEPT 运算符 ub?K,
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。 hq>Csj==@
C: INTERSECT 运算符 g=)J~1&p
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。 <g2_6C\j
注:使用运算词的几个查询结果行必须是一致的。 %g"eV4j
12、说明:使用外连接 "dh:-x6
A、left outer join: )hKS0`$|
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。 6gO9 MQY
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 GJ(d&o8
B:right outer join: CZ{k@z`r
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。 ` (4pu6uT
C:full outer join: XR+3j/zEQ
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。 +FFG#6e
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二、提升 E">T*ao
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) VrP}#3I
法一:select * into b from a where 1<>1 n]CbDbNw7)
法二:select top 0 * into b from a 5ua?I9fY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;DRTQn`m
insert into b(a, b, c) select d,e,f from b; (X[2TT3j!
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) [\ )Ge
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ffDc6*.Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. q`|CrOzO
4、说明:子查询(表名1:a 表名2:b) < a rZbM
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) &x:JD1T}
5、说明:显示文章、提交人和最后回复时间 ztM<J+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) -f(/B9}
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 9L eNe}9v
7、说明:在线视图查询(表名1:a ) #TJk-1XM*q
select * from (SELECT a,b,c FROM a) T where t.a > 1; m@xi0t
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 oUDVy_k
select * from table1 where time between time1 and time2 V2&^!#=s
select a,b,c, from table1 where a not between 数值1 and 数值2 dG'SZ&<
9、说明:in 的使用方法 7LZ^QC
select * from table1 where a [not] in ('值1','值2','值4','值6') (il0M=M
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ak:v3cQR
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) qztV,R T
11、说明:四表联查问题: > 6CV4 L
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 ..... E;\M1(\u
12、说明:日程安排提前五分钟提醒 WV<tyx9Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8s}J!/2
13、说明:一条sql 语句搞定数据库分页 zi]%Zp
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 +RZ~LA\+
14、说明:前10条记录 =ZYThfAEw
select top 10 * form table1 where 范围 N"5fmY<
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.) +54aO
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) VkmRh,T
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 D@Da0
(select a from tableA ) except (select a from tableB) except (select a from tableC) J@"utY6N
17、说明:随机取出10条数据 Xg<[fwW
select top 10 * from tablename order by newid() ~fN%WZ;_
18、说明:随机选择记录 2i=H"('G)+
select newid() PK6iY7Qp)
19、说明:删除重复记录 #} ,x @]p
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ~XM[>M\qB
20、说明:列出数据库里所有的表名 8}p8r|d!ls
select name from sysobjects where type='U' <EX7WA
21、说明:列出表里的所有的 |(IO=V4P
select name from syscolumns where id=object_id('TableName') Rhgj&4
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。 h,t|V}Wb
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 .=RlOK
显示结果: !F4;_A`X
type vender pcs JMV50 y
电脑 A 1 3 pWM~(#>-
电脑 A 1 +JdZPb
光盘 B 2 {Q(}DI
光盘 A 2 :>3=gex@^0
手机 B 3 _ *(bmJM
手机 C 3 gvavs+H%
23、说明:初始化表table1 cA`4:gp
TRUNCATE TABLE table1 ~4 #B'Gy[
24、说明:选择从10到15的记录 {+T/GBF-K=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc EYzg%\HH
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三、技巧 /="HqBI#i
1、1=1,1=2的使用,在SQL语句组合时用的较多 (RL>Hn;.
"where 1=1" 是表示选择全部 "where 1=2"全部不选, %|Qw9sbd
如: 3!9Z=-tD
if @strWhere !='' u:P~j
begin eQN.sl5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )najO*n
end n2-0.Er
else OKue" p
begin }7/e8 O2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' c$M%G)P
end }6m?d!m
我们可以直接写成 [[L-jq.'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .J.vC1 4gi
2、收缩数据库 #;r]/)>
--重建索引 Utl
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DBCC REINDEX rzLd"`
DBCC INDEXDEFRAG Lubrn"128
--收缩数据和日志 ZW4aY}~)$
DBCC SHRINKDB 4iX-( ir,
DBCC SHRINKFILE t 0O4GcAN
3、压缩数据库 H[&@}v,L
dbcc shrinkdatabase(dbname) d"<F!?8
4、转移数据库给新用户以已存在用户权限 QTJu7^O9
exec sp_change_users_login 'update_one','newname','oldname' E,"&-`/2v
go f05d ;
5、检查备份集 :[7lTp
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b5`KB75sbo
6、修复数据库 7Ua7A
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO ?[1SiJT
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w9~k]5
GO QApyP CH
ALTER DATABASE [dvbbs] SET MULTI_USER s;.=5wcvi?
GO Ob@Hng%v
7、日志清除 R 1zC.m
SET NOCOUNT ON =Viy^ieN$
DECLARE @LogicalFileName sysname, V'wi ^gq
@MaxMinutes INT, 9C}qVoNu
@NewSize INT v <h;Di@
USE tablename -- 要操作的数据库名 &a #GXf
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9%,;XQ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. DdjCn`jqlf
@NewSize = 1 -- 你想设定的日志文件的大小(M) x mo&![P
-- Setup / initialize -F`he=Ev9
DECLARE @OriginalSize int ,x#ztdvr
SELECT @OriginalSize = size EZj1jpL
FROM sysfiles mnQ'X-q3iO
WHERE name = @LogicalFileName _/x&<,3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bx;f`8SN
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [X"k>
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' r_o<SH
FROM sysfiles 7'j9rmTXs
WHERE name = @LogicalFileName uw_?O[ZA[
CREATE TABLE DummyTrans VXC4%
(DummyColumn char (8000) not null) .h8M
DECLARE @Counter INT, 19I:%$U3
@StartTime DATETIME, TVkcDS
@TruncLog VARCHAR(255) eE3-t/=
SELECT @StartTime = GETDATE(), ;'1Apy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' eV;me>,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) > V%Q O>C
EXEC (@TruncLog) JMsHK,(
-- Wrap the log if necessary. *{[d%B<lp
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired &o.iUk
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) eP |)SU
AND (@OriginalSize * 8 /1024) > @NewSize ,}7_[b)&V
BEGIN -- Outer loop. Bl4 dhBZoO
SELECT @Counter = 0 P(_(w
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) qZsnd7o{l.
BEGIN -- update Phlk1*1n
INSERT DummyTrans VALUES ('Fill Log') -1m vhR~
DELETE DummyTrans !sK#zAR2
SELECT @Counter = @Counter + 1 2PBepgQyPU
END z93nYY$`Y
EXEC (@TruncLog) 4*8&[b
END s`vSt*
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + jtLnj@,
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %!wq:~B1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' V.j#E1 P
FROM sysfiles IUawdB5CB
WHERE name = @LogicalFileName 3 2y[
DROP TABLE DummyTrans Rp4FXR jC
SET NOCOUNT OFF Wa, 7P2r
8、说明:更改某个表 1^sb T[%R
exec sp_changeobjectowner 'tablename','dbo' Sw
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9、存储更改全部表 D;C5,rNt
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $Sw,hb
@OldOwner as NVARCHAR(128), T#N80BH[
@NewOwner as NVARCHAR(128) UzJ!Y / 5
AS ASq`)Rz
DECLARE @Name as NVARCHAR(128) \7DCwu[0M
DECLARE @Owner as NVARCHAR(128) hU+#S(t>b
DECLARE @OwnerName as NVARCHAR(128) pXNtN5@FQ
DECLARE curObject CURSOR FOR kPedX
select 'Name' = name, ZIy(<0
'Owner' = user_name(uid) d~/xGB`<
from sysobjects o@',YF>OQ
where user_name(uid)=@OldOwner
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order by name Xv&%2-V;
OPEN curObject PHQcstW
FETCH NEXT FROM curObject INTO @Name, @Owner 2<m
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WHILE(@@FETCH_STATUS=0) 'tSnH&c
BEGIN cf&C|U
if @Owner=@OldOwner <G}m #
begin vVdxi9yk
set @OwnerName = @OldOwner + '.' + rtrim(@Name) _KxX&THaj
exec sp_changeobjectowner @OwnerName, @NewOwner i8eA_Q
end {[lx!QF 8&
-- select @name,@NewOwner,@OldOwner V^WQ6G1
FETCH NEXT FROM curObject INTO @Name, @Owner %|bN@@
END 7_7xL(F/
close curObject pKYLAt+^>
deallocate curObject BArJ"t*/z
GO 3l+|&q[v
10、SQL SERVER中直接循环写入数据 0@w&J9yG
declare @i int -BjEL;
set @i=1 /rOnm=P+Q
while @i<30 Y`q!V=
begin d}pGeU'
insert into test (userid) values(@i) d4V 2[TX
set @i=@i+1 \CDAFu#
end P 4H*jy@?
小记存储过程中经常用到的本周,本月,本年函数 aYR\ <02
Dateadd(wk,datediff(wk,0,getdate()),-1) 9Mnem*
Dateadd(wk,datediff(wk,0,getdate()),6) 'l8eH$
Dateadd(mm,datediff(mm,0,getdate()),0) n }TTq6B
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) sI4QI\*4
Dateadd(yy,datediff(yy,0,getdate()),0) [e1\A&T
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) pj j}K
上面的SQL代码只是一个时间段 O/nqNQ?<
Dateadd(wk,datediff(wk,0,getdate()),-1) y^, "gD
Dateadd(wk,datediff(wk,0,getdate()),6) '&/(oJ;O~
就是表示本周时间段. EO"=\C,
下面的SQL的条件部分,就是查询时间段在本周范围内的: Px$'(eMj^3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) :nt}7Dn'
而在存储过程中 *:(1K%g
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?'T"?b<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) HoMQt3C