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。 f]^(|*6
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一、基础 ;26a8g(
1、说明:创建数据库 O(!J^J3_z
CREATE DATABASE database-name 36,qh.LKn
2、说明:删除数据库 (~?P7RnU%
drop database dbname @`G_6<.`
3、说明:备份sql server -PbGNF
--- 创建 备份数据的 device afqLTWUS
USE master 1y$Bz?4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =SA@3)kHH
--- 开始 备份 IVzJ|
BACKUP DATABASE pubs TO testBack ,@tYD(Z
4、说明:创建新表 \m1r(*Ar
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lsCD%P
根据已有的表创建新表: wA|m/SZx
A:create table tab_new like tab_old (使用旧表创建新表) 0R\lm<&
B:create table tab_new as select col1,col2... from tab_old definition only )}\jbh>RH
5、说明:删除新表 ;hA>?o_i(
drop table tabname yw41/jHF
6、说明:增加一个列 R9f*&lj
Alter table tabname add column col type - U!:.
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 K%P$#a
7、说明:添加主键: Alter table tabname add primary key(col) iK#5HW{
说明:删除主键: Alter table tabname drop primary key(col) JBtcl#|
8、说明:创建索引:create [unique] index idxname on tabname(col....) SSYE&
删除索引:drop index idxname fKY6stJE
注:索引是不可更改的,想更改必须删除重新建。 |k$[+53A
9、说明:创建视图:create view viewname as select statement {'l^{"GO"
删除视图:drop view viewname Aa[p7{e
10、说明:几个简单的基本的sql语句 |Kky+*
选择:select * from table1 where 范围 UBs'3M
插入:insert into table1(field1,field2) values(value1,value2) m]R< :_
删除:delete from table1 where 范围 ,Bk mf|
更新:update table1 set field1=value1 where 范围 N&K:Jp
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Q9t BHz
排序:select * from table1 order by field1,field2 [desc] ~>3$Id:
总数:select count as totalcount from table1 9eo$Duws
求和:select sum(field1) as sumvalue from table1 KFCrJ)
平均:select avg(field1) as avgvalue from table1 YQ}Rg5o
最大:select max(field1) as maxvalue from table1 ogbLs)&+a
最小:select min(field1) as minvalue from table1 H{
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11、说明:几个高级查询运算词 >0~|iRySi
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A: UNION 运算符 Bwj^9J/ob
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 }
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B: EXCEPT 运算符 6T! *YrS
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 {Lwgj7|~
C: INTERSECT 运算符 vz#VW
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 `of 5h*k
注:使用运算词的几个查询结果行必须是一致的。 j2\bCGY
12、说明:使用外连接 <k-&Lh:o3
A、left outer join: =o^oMn
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 8ME_O~,N
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2~Z P[wr
B:right outer join: FPE[}
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 YHAhF@&
C:full outer join: 5+].$
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。 S9S8T+
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二、提升 /k qW
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) OJPxV~y
法一:select * into b from a where 1<>1 }-?_c#G3
法二:select top 0 * into b from a t}>6"^}U
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *%5.{J!
insert into b(a, b, c) select d,e,f from b; x9k(mn%,
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) _p <W
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Fi vgOa
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 6d& dB
4、说明:子查询(表名1:a 表名2:b) 3`uv/O2~i
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) secD
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5、说明:显示文章、提交人和最后回复时间 _TfG-Ae
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |=L~>G
6、说明:外连接查询(表名1:a 表名2:b) ^2%_AP0=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :IlRn`9X`
7、说明:在线视图查询(表名1:a ) [* ,k
select * from (SELECT a,b,c FROM a) T where t.a > 1; ,*$L_itL
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 `WQz_}TqB
select * from table1 where time between time1 and time2 /yPFts_q
select a,b,c, from table1 where a not between 数值1 and 数值2 ,~u 5SR
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') Nd'+s>d0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 XdE#l/#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) M}=X/*T
11、说明:四表联查问题: 4Xi
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... S+Z_Qf
12、说明:日程安排提前五分钟提醒 GEj/Z};;[b
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 \ofWD{*j
13、说明:一条sql 语句搞定数据库分页 1;?n]L`T
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 JX8Hn |
14、说明:前10条记录 Zz}Wg@&
select top 10 * form table1 where 范围 >Eg/ir0
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) t0h@i`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) nI7G"f[%r;
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Sm-gi|A
(select a from tableA ) except (select a from tableB) except (select a from tableC) gw' uY$
17、说明:随机取出10条数据 DjY&)oce(
select top 10 * from tablename order by newid() z(b0U6)qQ
18、说明:随机选择记录 j3 ,6UjlU
select newid() tkX7yg>`
19、说明:删除重复记录 Y5?*=eM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) is}6cR
20、说明:列出数据库里所有的表名 T9w;4XF
select name from sysobjects where type='U' eH,r%r,
21、说明:列出表里的所有的 {JTO
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select name from syscolumns where id=object_id('TableName') TbX#K:l
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。 e/hA>
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 f'&30lF
显示结果: ]S;^QZ
type vender pcs dS]TTU1
电脑 A 1 ,l/~epx4v)
电脑 A 1 hG51jVYtw
光盘 B 2 Lc 4\i
光盘 A 2 ?#~3%$>
手机 B 3 lZ]x #v
手机 C 3 tQ0iie1Ys
23、说明:初始化表table1 ?.Mw
TRUNCATE TABLE table1 ERD( qL.J
24、说明:选择从10到15的记录 f$#--*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc gS{hfDpk,h
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三、技巧 mU0j K@^&M
1、1=1,1=2的使用,在SQL语句组合时用的较多 qQK0s*^W
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Mh
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如: 6[3oOO:uo
if @strWhere !='' \yt-_W=[
begin Sl,X*[HGd
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Mj&`Y
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end D>Ij
else d&[Ct0!++u
begin ~*"]XE?M
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;#-yyU
end dxHKXw
我们可以直接写成 3j<:g%5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere {l/j?1Dxq
2、收缩数据库 ab"6]%_
--重建索引 CB V(H$d
DBCC REINDEX ,liFo.kT8%
DBCC INDEXDEFRAG w_zUA'n+
--收缩数据和日志 X*ZTn
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DBCC SHRINKDB '"u>;Bq
DBCC SHRINKFILE 8 KDF*%7'
3、压缩数据库 'dJ#NT25
dbcc shrinkdatabase(dbname) {Yq"%n'0
4、转移数据库给新用户以已存在用户权限 EJC{!06L'/
exec sp_change_users_login 'update_one','newname','oldname' )}ygzKEa
go }U <T>0
5、检查备份集 'Mp8!9=&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' G bW1Lq&"
6、修复数据库 F3d: W:^_
ALTER DATABASE [dvbbs] SET SINGLE_USER Y2lBQp8'|
GO +,oEcCi
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wxC&KrRF
GO (4:&tm/;
ALTER DATABASE [dvbbs] SET MULTI_USER ^G:}%4
GO j}P
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7、日志清除 )v\zaz
SET NOCOUNT ON M"XILNV-~
DECLARE @LogicalFileName sysname, poLzgd
@MaxMinutes INT, G@$Y6To[
@NewSize INT bogw /)1
USE tablename -- 要操作的数据库名 ,Sz`$'^c
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \tv^],^`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. tc-pVw:TV
@NewSize = 1 -- 你想设定的日志文件的大小(M) t<8vgdD
-- Setup / initialize bUv}({
DECLARE @OriginalSize int yg}zK>j^vC
SELECT @OriginalSize = size pF0sXvWGG
FROM sysfiles _FpZc?=
WHERE name = @LogicalFileName 8+}yf.`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + RbOEXH*]
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + cV;<!f+
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' VTS7K2lBvX
FROM sysfiles y$i^C: N
WHERE name = @LogicalFileName 0)<\jo1 F
CREATE TABLE DummyTrans `O5 Hzb(}
(DummyColumn char (8000) not null) p2m@0ou
DECLARE @Counter INT, "gt-bo.,
@StartTime DATETIME, 6yn34'yw
@TruncLog VARCHAR(255) j ?c"BF.
SELECT @StartTime = GETDATE(), _LVwjZX[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5hxG\f#}?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _xKu EU}
EXEC (@TruncLog) MH wjJ
-- Wrap the log if necessary. 4o/}KUu(*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired g5",jTn#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Z<_"Tk;!',
AND (@OriginalSize * 8 /1024) > @NewSize ,K/l;M5I
BEGIN -- Outer loop. XK*55W&og
SELECT @Counter = 0 s&Bk@a8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^nO0/nqz]
BEGIN -- update xi+bBqg<.K
INSERT DummyTrans VALUES ('Fill Log') ;)nkY6-
DELETE DummyTrans X667*L^
SELECT @Counter = @Counter + 1 Q:L^DZkGV
END 9F~e^v]zp
EXEC (@TruncLog) 0iKSUwps
END "+0Yhr ?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,Yp+&&p.
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 8m prK`p
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' &*Sgyk
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FROM sysfiles ;+-@AYl
WHERE name = @LogicalFileName Fx@ovI- 5
DROP TABLE DummyTrans g?7I7W~?`
SET NOCOUNT OFF kjj4%0"
8、说明:更改某个表 d#tqa`@~
exec sp_changeobjectowner 'tablename','dbo' i`nmA-Zj[
9、存储更改全部表 a *hWODYn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch yr;~M{{4
@OldOwner as NVARCHAR(128), Q>ZxJ!B<k
@NewOwner as NVARCHAR(128) VtTTvP3
AS Ym% $!#
DECLARE @Name as NVARCHAR(128) 9#;GG3
DECLARE @Owner as NVARCHAR(128) (7X|W<xT
DECLARE @OwnerName as NVARCHAR(128) TTDcVG_}
DECLARE curObject CURSOR FOR )a7nr<)aU
select 'Name' = name, "V=IG{.
'Owner' = user_name(uid) I ~U1vtgp
from sysobjects )7aUDsu>4
where user_name(uid)=@OldOwner Ri
order by name #oYPe:8|m
OPEN curObject 6D\$K
FETCH NEXT FROM curObject INTO @Name, @Owner B5A/Iv)2
WHILE(@@FETCH_STATUS=0) w$)NW57[|
BEGIN C{*' p+f
if @Owner=@OldOwner {+3
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begin h]+UK14m
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *jf%Wj)0M
exec sp_changeobjectowner @OwnerName, @NewOwner -$ VP#%
end CD!Aa
-- select @name,@NewOwner,@OldOwner [
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FETCH NEXT FROM curObject INTO @Name, @Owner 7^oO
N+=d
END |#b]e|aP
close curObject 5V $H?MW>
deallocate curObject mi';96
GO LJ8 t@ui
10、SQL SERVER中直接循环写入数据 >fq]c
declare @i int sQ}E4Iq1#S
set @i=1 ;_K3/:
while @i<30 G (3wI}
begin )K}-z+$)k
insert into test (userid) values(@i) mf W}^mu
set @i=@i+1 ufF>I
end L*8U.{NY
小记存储过程中经常用到的本周,本月,本年函数 _'*Vcu`Y
Dateadd(wk,datediff(wk,0,getdate()),-1) mEZHrr J
Dateadd(wk,datediff(wk,0,getdate()),6) Ueb&<tS
Dateadd(mm,datediff(mm,0,getdate()),0) ` ;}w!U
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^\f1zg9I
Dateadd(yy,datediff(yy,0,getdate()),0) /ucS*m:<x
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #FhgKwx
上面的SQL代码只是一个时间段 mx!EuF$I
Dateadd(wk,datediff(wk,0,getdate()),-1) Dq~\U&U\$
Dateadd(wk,datediff(wk,0,getdate()),6) '% if< /
就是表示本周时间段. /prR;'ks
下面的SQL的条件部分,就是查询时间段在本周范围内的: w7%.EA{N
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <-h[I&."
而在存储过程中 {y%|Io`P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) '>^!a!<G
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) !jTxMf