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。 .VD:FFkW
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一、基础 nDG41)|
1、说明:创建数据库 Y8i'=Po%,
CREATE DATABASE database-name p. %lE!v
2、说明:删除数据库 P5?M"j0/^
drop database dbname !+R_Z#gB
3、说明:备份sql server |.]g&m)y^h
--- 创建 备份数据的 device 9nGS"E l{
USE master 5~ip N/)E
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -F->l5
--- 开始 备份 :`Sd5b>
BACKUP DATABASE pubs TO testBack K>a@AXC
4、说明:创建新表 au+6ookT
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 7Be\^%
根据已有的表创建新表: vV$6fvS
A:create table tab_new like tab_old (使用旧表创建新表) V;N'?Gu
B:create table tab_new as select col1,col2... from tab_old definition only =6YffXa_s
5、说明:删除新表 :Vnus
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drop table tabname .\rJ|HpZ1J
6、说明:增加一个列 XYrZI/R
Alter table tabname add column col type }LA7ku
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。 Lb=4\ _
7、说明:添加主键: Alter table tabname add primary key(col) "e ;wN3/bF
说明:删除主键: Alter table tabname drop primary key(col) b<E0|VW
8、说明:创建索引:create [unique] index idxname on tabname(col....) iJaA&z5sr
删除索引:drop index idxname f53WDI6
注:索引是不可更改的,想更改必须删除重新建。 PrQs_tNi
9、说明:创建视图:create view viewname as select statement Z*Lv!6WS
删除视图:drop view viewname QnMN8Q9
10、说明:几个简单的基本的sql语句 i_'u:P<t
选择:select * from table1 where 范围 b%_[\((
插入:insert into table1(field1,field2) values(value1,value2) g[D`.
删除:delete from table1 where 范围 b!l/O2
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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! yv+DM`0
排序:select * from table1 order by field1,field2 [desc] X"fSM
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总数:select count as totalcount from table1 N*{>8iFo4
求和:select sum(field1) as sumvalue from table1 q% pjY
平均:select avg(field1) as avgvalue from table1 gZ 6Hj62D
最大:select max(field1) as maxvalue from table1 iS#m{1m$$
最小:select min(field1) as minvalue from table1 uzO3 _.4Y
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11、说明:几个高级查询运算词 nNP{>\x;"
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A: UNION 运算符 K[Ao_v2g
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。 }DzN-g<K
B: EXCEPT 运算符 48W-Tf6v|
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。 MU#$tXmnC
C: INTERSECT 运算符 a"pejW`m
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。 ^hIKDc!.m
注:使用运算词的几个查询结果行必须是一致的。 bA*T1Db,t>
12、说明:使用外连接
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A、left outer join: Ng;Fhv+
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。 RXWS,rF
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 0Ik}\lcn
B:right outer join: `mo>~c7
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。 (.J8Q
C:full outer join: :d`8:gv?
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。 d\{a&\v
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二、提升 0ofl,mXW
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) *Jm U",X
法一:select * into b from a where 1<>1 EC0M0qQ
法二:select top 0 * into b from a vp#r:+=
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) W*D].|
insert into b(a, b, c) select d,e,f from b; !tr
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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) B'`
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R`F8J}X_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 7J$5dFV2
4、说明:子查询(表名1:a 表名2:b) sXmo.{Ayb
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ].,TSnb
5、说明:显示文章、提交人和最后回复时间 AcCM
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b PdNxuy
6、说明:外连接查询(表名1:a 表名2:b) 'RjMwJy{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c r1!]<= &\
7、说明:在线视图查询(表名1:a ) |Je+y;P7
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 sxBRg=
select * from table1 where time between time1 and time2 A_\ZY0Xt
select a,b,c, from table1 where a not between 数值1 and 数值2 ko<iG]Dv'
9、说明:in 的使用方法 JHCV7$RS
select * from table1 where a [not] in ('值1','值2','值4','值6') O&c~7tM%
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Y
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) H@R2mw
11、说明:四表联查问题: :.,3Zw{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 ..... ;zl/
12、说明:日程安排提前五分钟提醒 c6NCy s
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _Mis-K:]{?
13、说明:一条sql 语句搞定数据库分页 e2xqKG
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 te b~KM
14、说明:前10条记录 :/
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select top 10 * form table1 where 范围 :%hxg
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.) ^"N sb &
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (KDv>@5
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 .$,.w__m~
(select a from tableA ) except (select a from tableB) except (select a from tableC) <Gr775"
17、说明:随机取出10条数据 .+"SDtoX
select top 10 * from tablename order by newid() i%R2#F7I
18、说明:随机选择记录 ^9Je8 @Yu
select newid() yfD)|lK
19、说明:删除重复记录 [Bz'c1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L'J Ekji"
20、说明:列出数据库里所有的表名 jSj
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select name from sysobjects where type='U' L,F )l2
21、说明:列出表里的所有的 Y_)aoRjB
select name from syscolumns where id=object_id('TableName') 2Rp'ju~O)/
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。 FrNW@
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 V %cU@
显示结果: 8;YN`S!o
type vender pcs y/}>)o4Q
电脑 A 1 w]{NaNIeq1
电脑 A 1 TZ7{cekQ
光盘 B 2 5[Ryc[
光盘 A 2 :K3nJ1G&
手机 B 3 wghz[qe
手机 C 3 g]g2`ab |
23、说明:初始化表table1 ,cvLvN8
TRUNCATE TABLE table1 Cz\(.MWNZ
24、说明:选择从10到15的记录 USnKj_e
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc BHwQB2t gc
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三、技巧 *6)u5
1、1=1,1=2的使用,在SQL语句组合时用的较多 O/IW.t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #pxc6W /
如: u_o>v{&i
if @strWhere !='' N>OF
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begin j/bebR}X
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere eo4<RDe<
end =GQ?P*x|$
else $
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begin bp6 La`+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =*q:R9V
end BEM+FG
我们可以直接写成 icF -`m
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere yKO84cSl
2、收缩数据库 hnM|=[wM
--重建索引 (~TP
DBCC REINDEX :&dY1.<N+
DBCC INDEXDEFRAG 181-m7W
--收缩数据和日志 lC6#EU;
DBCC SHRINKDB V|{ )P@Q
DBCC SHRINKFILE (J):
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3、压缩数据库 :&`Yz
dbcc shrinkdatabase(dbname) :H<u@%
4、转移数据库给新用户以已存在用户权限 p]:~z|.Ba
exec sp_change_users_login 'update_one','newname','oldname' cW),Y|8
go 1+o >#8D
5、检查备份集 hX=+%^c%_A
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' pM\)f
6、修复数据库 dH!k{3bL
ALTER DATABASE [dvbbs] SET SINGLE_USER V0L^pDLOV
GO 71Ssk|L
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2s
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GO 6(oGU4
ALTER DATABASE [dvbbs] SET MULTI_USER g4d5G=y
GO ?4q6>ipx
7、日志清除 ZzI^*Nyg
SET NOCOUNT ON Bl'
DECLARE @LogicalFileName sysname, 2Z,;#t
@MaxMinutes INT, W #qM$
@NewSize INT J mFzSR?}
USE tablename -- 要操作的数据库名 wH!]B-hn
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z|d_G}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [}lv!KmzW
@NewSize = 1 -- 你想设定的日志文件的大小(M) 622mNY
-- Setup / initialize b_Ba0h=
DECLARE @OriginalSize int hS
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SELECT @OriginalSize = size lyZof_/*
FROM sysfiles 'y}A3RqN
WHERE name = @LogicalFileName yN~=3b>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + SNff
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #B'WT{B$/~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &)fPz-s
FROM sysfiles ClVMZ
WHERE name = @LogicalFileName fylW)W4C
CREATE TABLE DummyTrans %<DRrKt
(DummyColumn char (8000) not null) :!tQqy2
DECLARE @Counter INT, MkJL9eG
@StartTime DATETIME, yYdXAenQ
@TruncLog VARCHAR(255) %
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SELECT @StartTime = GETDATE(), xvp{F9~qT
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' i>,5b1x~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )KBv[|
EXEC (@TruncLog) r-Z'
-- Wrap the log if necessary. ])~*)I~Y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired giaO7Qh~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) x6,S#p
AND (@OriginalSize * 8 /1024) > @NewSize 7GK| A{r
BEGIN -- Outer loop. 1 ,D2][
SELECT @Counter = 0 sd8o&6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \~y>aYy
BEGIN -- update s o~p+]
INSERT DummyTrans VALUES ('Fill Log') yo
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DELETE DummyTrans 3O#7OL68v
SELECT @Counter = @Counter + 1 VWfrcSZg6M
END kmov(V
EXEC (@TruncLog) 7Zu!s]t
END tinN$o
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + h.2!d0j]
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + YLobBtXc9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Z"!C
FROM sysfiles ?m?e2{]u,
WHERE name = @LogicalFileName 3<JZt.|
DROP TABLE DummyTrans u%}vTCg*p
SET NOCOUNT OFF JxD@y}ZYE
8、说明:更改某个表 'a"<uk3DT
exec sp_changeobjectowner 'tablename','dbo' D;d;:WT5
9、存储更改全部表 UdL`.D,
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7*`ldao~
@OldOwner as NVARCHAR(128), f4g(hjETbu
@NewOwner as NVARCHAR(128) zo\XuoZ
AS *ZaK+ B
DECLARE @Name as NVARCHAR(128) @KS:d\l}U
DECLARE @Owner as NVARCHAR(128) (V=lK6WQm
DECLARE @OwnerName as NVARCHAR(128) *VRFs=
DECLARE curObject CURSOR FOR ojIh;e
select 'Name' = name, f"-<Z_
'Owner' = user_name(uid) cPS!%?}I
from sysobjects sgB3i`_M
where user_name(uid)=@OldOwner ;H\,w/E9
order by name {L4^IKI
OPEN curObject P_ZguNH
FETCH NEXT FROM curObject INTO @Name, @Owner 5.\!k8a
WHILE(@@FETCH_STATUS=0) `DA=';>Y
BEGIN C)ChF`Ru':
if @Owner=@OldOwner eq4<
begin t"BpaA^gO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6Jj)[ R\5=
exec sp_changeobjectowner @OwnerName, @NewOwner ,bH
end ?xG #4P<C=
-- select @name,@NewOwner,@OldOwner ;G\rhk
FETCH NEXT FROM curObject INTO @Name, @Owner r% B5@+{so
END `b% /.%]$
close curObject 0cS.|\ZTA
deallocate curObject =_,OucKkYG
GO zzW^AvR
10、SQL SERVER中直接循环写入数据 T%]:
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declare @i int Jp,ohVRNq
set @i=1 , 1`eH[
while @i<30 ]mqB&{g
begin f9\7v_
insert into test (userid) values(@i) iu1iO;q
set @i=@i+1 1zp,Suv
end CRqa[boU*
小记存储过程中经常用到的本周,本月,本年函数 |w>DZG!}1-
Dateadd(wk,datediff(wk,0,getdate()),-1) ev@1+7(
Dateadd(wk,datediff(wk,0,getdate()),6) )8N/t6Q
Dateadd(mm,datediff(mm,0,getdate()),0) tx.YW9xD
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) RI%l& Hm
Dateadd(yy,datediff(yy,0,getdate()),0) Ugs<WVp$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Lh,<q
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上面的SQL代码只是一个时间段 }=L
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Dateadd(wk,datediff(wk,0,getdate()),-1) X:!%"K%}
Dateadd(wk,datediff(wk,0,getdate()),6) \o3i9Q9C
就是表示本周时间段. [ z&y]~
下面的SQL的条件部分,就是查询时间段在本周范围内的: kO9yei
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) SBF3\
而在存储过程中 #".{i+3E
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) lA ,%'+-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ![V<vIy