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。 5:|5NX[.b
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一、基础 Tv3 ZNh
1、说明:创建数据库 P?n!fA>!
CREATE DATABASE database-name O~d!*A
2、说明:删除数据库 psRm*,*O
drop database dbname y5a^xRDw
3、说明:备份sql server EN.yU!N.4
--- 创建 备份数据的 device lGG1d
USE master w,8 M
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ] >ipC,v
--- 开始 备份 Djf2ir'
BACKUP DATABASE pubs TO testBack dG7sY
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4、说明:创建新表 ~\<ZWU<BE
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^.kas7<
根据已有的表创建新表: qa^x4xZM
A:create table tab_new like tab_old (使用旧表创建新表) ;~~Oc
B:create table tab_new as select col1,col2... from tab_old definition only a,cDj
5、说明:删除新表 cdU2ph_
drop table tabname R$,`}@VqZ3
6、说明:增加一个列 nq/xD;q
Alter table tabname add column col type ?0[%+AD hM
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 &[cL%pP
7、说明:添加主键: Alter table tabname add primary key(col) w])~m1yW
说明:删除主键: Alter table tabname drop primary key(col) >4M_jC.
8、说明:创建索引:create [unique] index idxname on tabname(col....) N_pJE?
删除索引:drop index idxname q(.%f3(
注:索引是不可更改的,想更改必须删除重新建。 `H/HLCt
9、说明:创建视图:create view viewname as select statement Cy6[p
删除视图:drop view viewname 6El%T]^
10、说明:几个简单的基本的sql语句 AaTtYd
选择:select * from table1 where 范围 O-T/H-J`
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 =5Q;quKu^5
更新:update table1 set field1=value1 where 范围 (!X:[Ah*$
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! u6r-{[W}
排序:select * from table1 order by field1,field2 [desc] fY%Sw7ql<
总数:select count as totalcount from table1 NBMY1Xgj
求和:select sum(field1) as sumvalue from table1 yvDzxu
平均:select avg(field1) as avgvalue from table1 4vqu(w8
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最大:select max(field1) as maxvalue from table1 R<UjhCvx.
最小:select min(field1) as minvalue from table1 aE{b65'Dt
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11、说明:几个高级查询运算词 $Uewv
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A: UNION 运算符 D@
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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。 vMRKs#&8
B: EXCEPT 运算符 2DV{gF
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。 3'/wRK l
C: INTERSECT 运算符 ) ]~HjA;
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。 %< j=&
注:使用运算词的几个查询结果行必须是一致的。 kI[EG<N1k
12、说明:使用外连接 bjT0Fi0-
A、left outer join: }_?7k0EZ@
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。 eazP'(rc
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 ;4qalxzu
B:right outer join: =Fj:#s
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。 z%g<&Cq
C:full outer join: Ci*TX
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。 ["L?t ^*G
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二、提升 HYg_{
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) xD1wHp!+
法一:select * into b from a where 1<>1 Y(A?ib~K
法二:select top 0 * into b from a |g;XC^!%=o
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) sJM}p5V
insert into b(a, b, c) select d,e,f from b; ~{NDtB)
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) UT{Nly8u
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 pwZ &2&|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t]&n_]`{.
4、说明:子查询(表名1:a 表名2:b) wy-!1wd
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) "V:UQ<a\
5、说明:显示文章、提交人和最后回复时间 R6:N`S]&d[
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6|jE3rHw
6、说明:外连接查询(表名1:a 表名2:b) 0?`#ko7~d
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c z.H`a+cl
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; }Ql;% 7
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 Ahwu'mgnC
select * from table1 where time between time1 and time2 Tf[]vqa`G
select a,b,c, from table1 where a not between 数值1 and 数值2 A6U6SvM;
9、说明:in 的使用方法 bg=`
select * from table1 where a [not] in ('值1','值2','值4','值6') ?b7vc^E&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 gTQ6B,`/8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Xs?>6i@$$
11、说明:四表联查问题: rU~"A
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 ..... (f.A5~e
12、说明:日程安排提前五分钟提醒 jyT(LDsS
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 VI+Y 4T@
13、说明:一条sql 语句搞定数据库分页 ePY K^D
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 ~ZDdzp>
14、说明:前10条记录 tllg$CQ5
select top 10 * form table1 where 范围 )eG&"3kFe!
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.) oDP|>yXC)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }`g*pp*
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 Anm5Cvt;i
(select a from tableA ) except (select a from tableB) except (select a from tableC) Ux<h`
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17、说明:随机取出10条数据 Fwqv1+
select top 10 * from tablename order by newid() _j2`#|oG
18、说明:随机选择记录 $fn^i.
select newid() 4C[gW
19、说明:删除重复记录 d)AkA\neWo
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) a*D|$<V
20、说明:列出数据库里所有的表名 \C6m.%%={R
select name from sysobjects where type='U' (J;?eeP
21、说明:列出表里的所有的 50Jr(OeU<
select name from syscolumns where id=object_id('TableName') ujSzm=_P
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。 _HL3XT
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 [&4y@
显示结果: tw(2V$J
type vender pcs ZEMo`O
电脑 A 1 ?@,:\ ,G
电脑 A 1 z&:[.B
光盘 B 2 u,]yd*
光盘 A 2 lGz0K5P{
手机 B 3 XDWERvIj
手机 C 3 $R5-JvJJH
23、说明:初始化表table1 ~iSW^mi
TRUNCATE TABLE table1 N1$P6ZF
24、说明:选择从10到15的记录 "LWp/
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?=G H{
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三、技巧 hh{liS% 10
1、1=1,1=2的使用,在SQL语句组合时用的较多 d"cfSH;h
"where 1=1" 是表示选择全部 "where 1=2"全部不选, (M=Br
如: uXC?fMWp.
if @strWhere !='' JQCwI`%i
begin !K2[S
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere RAxz+1JT
end ]aR4U`
else +Oscy-;
begin e{O5y8,
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :Ry24X
end %qHT!aP
我们可以直接写成 = V , _
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [4t KJ+v
2、收缩数据库 Y>%NuL|s
--重建索引 +OmSR*fA0
DBCC REINDEX I6fpXPP).
DBCC INDEXDEFRAG {MtB!x
--收缩数据和日志 mc=*wr$
DBCC SHRINKDB E.3}a>f
DBCC SHRINKFILE Rt|Hma
3、压缩数据库 n\YxRs7
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dbcc shrinkdatabase(dbname) `3KprpE8v
4、转移数据库给新用户以已存在用户权限 r?TK@^z
exec sp_change_users_login 'update_one','newname','oldname' }M9al@"
go N'1~ wxd
5、检查备份集 :&%;s*-9
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6.jZy~
6、修复数据库 Hn~1x'$
ALTER DATABASE [dvbbs] SET SINGLE_USER 6b|`[t
GO E~P0}'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $5IrM7i
GO QhUraZ
ALTER DATABASE [dvbbs] SET MULTI_USER e2fct|'
GO "=(;l3-o
7、日志清除 &^H
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SET NOCOUNT ON h~@+M5r,
DECLARE @LogicalFileName sysname, d/&|%Z
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@MaxMinutes INT, \_E.%K
@NewSize INT fz3*oJ'
USE tablename -- 要操作的数据库名 /WfVG\NF
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 g@k9w{_
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
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@NewSize = 1 -- 你想设定的日志文件的大小(M) jhG7sS|
-- Setup / initialize DE ws+y-*
DECLARE @OriginalSize int hl:eF:'hm
SELECT @OriginalSize = size 4QNR_w
FROM sysfiles ->8q, W2A
WHERE name = @LogicalFileName pxx(BE
SELECT 'Original Size of ' + db_name() + ' LOG is ' + r\d:fot
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <3}l8Z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' AF$ o>f
FROM sysfiles ^Q>*f/.KN
WHERE name = @LogicalFileName JWL J<z
CREATE TABLE DummyTrans -/%jeDKp
(DummyColumn char (8000) not null) Ol[gck|~
DECLARE @Counter INT, o}A #-
@StartTime DATETIME, ea0tx3'
@TruncLog VARCHAR(255) zIFL?8!H9{
SELECT @StartTime = GETDATE(), >G2-kL_
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' PuaosMn(9
DBCC SHRINKFILE (@LogicalFileName, @NewSize) D8Rmxq!
EXEC (@TruncLog) PNgMLQI6
-- Wrap the log if necessary. ai4^NJn
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired a`*WpP \+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :$aW@?zAY
AND (@OriginalSize * 8 /1024) > @NewSize [r8 d+
BEGIN -- Outer loop. MF}Lv1/[-J
SELECT @Counter = 0 >EtP^Lu~f_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) HW726K*
BEGIN -- update dA/o4co
INSERT DummyTrans VALUES ('Fill Log') |vz;bJG
DELETE DummyTrans zDyeAxh4
SELECT @Counter = @Counter + 1 x Ui!|c
END QJWES%m`
EXEC (@TruncLog) 9Oyi:2A
END k+$4?/A
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PAV2w_X~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~iZF~PQ1_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' HDyZzjgG
FROM sysfiles \STvBI?
WHERE name = @LogicalFileName Qu FCc1Q
DROP TABLE DummyTrans vXyo
SET NOCOUNT OFF f+Me dc~
8、说明:更改某个表 W;dzLgc
exec sp_changeobjectowner 'tablename','dbo' 2gAdZE&Y
9、存储更改全部表 FM"BTA:C
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~#_$?_/(
@OldOwner as NVARCHAR(128), lMez!qx,=
@NewOwner as NVARCHAR(128) N>%KV8>{L
AS y=xe<#L
DECLARE @Name as NVARCHAR(128) Xl6ZV,1=n7
DECLARE @Owner as NVARCHAR(128) cGta4;
DECLARE @OwnerName as NVARCHAR(128) IQ=|Kj9h
DECLARE curObject CURSOR FOR ,7jiHF
select 'Name' = name, *.%)rm
'Owner' = user_name(uid) x[W]?`W3r~
from sysobjects y~c[sW
where user_name(uid)=@OldOwner ptyDv
order by name H)T# R?
OPEN curObject S\g7wXH
FETCH NEXT FROM curObject INTO @Name, @Owner BON""yIC
WHILE(@@FETCH_STATUS=0) !9 LAXM
BEGIN Y~hd<8 ~
if @Owner=@OldOwner -^Km}9g
begin \w[ZY$/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Z?c=t-yqp
exec sp_changeobjectowner @OwnerName, @NewOwner X1[R*a/p
end JS?l?~
-- select @name,@NewOwner,@OldOwner p]|ME
FETCH NEXT FROM curObject INTO @Name, @Owner ":#x\;
END w^E]N
close curObject GdeR#%z
deallocate curObject R
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GO
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10、SQL SERVER中直接循环写入数据 ZX6=D>)u
declare @i int _AHB|P I
set @i=1 3KFrVhB=
while @i<30 *Gh8nQbh
begin 1qKxg
insert into test (userid) values(@i) k>;r9^D
set @i=@i+1 i-s?"Fk
end W<N QUf[=
小记存储过程中经常用到的本周,本月,本年函数 :G=1$gb
Dateadd(wk,datediff(wk,0,getdate()),-1) rn[}{1I33Q
Dateadd(wk,datediff(wk,0,getdate()),6) Y1_6\zpA
Dateadd(mm,datediff(mm,0,getdate()),0) lPQ
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \]#;!6ge
Dateadd(yy,datediff(yy,0,getdate()),0) _B7?C:8Q-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) YSz$` 7i
上面的SQL代码只是一个时间段 ?CW^*So
Dateadd(wk,datediff(wk,0,getdate()),-1) :mV7)oWH
Dateadd(wk,datediff(wk,0,getdate()),6) _E<O+leWf
就是表示本周时间段. X1V}%@3:
下面的SQL的条件部分,就是查询时间段在本周范围内的: _KhEwd
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]#-/i2-K
而在存储过程中 VBsFT2XiL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) iLd"tn'
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) f+aS2k(e>