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。 >
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一、基础 <61T)7
1、说明:创建数据库 Vrzx;V%
CREATE DATABASE database-name eTemRNz
2、说明:删除数据库 RiqYC3Ka
drop database dbname 9&fS<Hk
3、说明:备份sql server A(2_hl-
--- 创建 备份数据的 device 0]?} kY
USE master i,1=5@rw5
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2W:R{dHE
--- 开始 备份 3
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BACKUP DATABASE pubs TO testBack Fxdu)F,~u
4、说明:创建新表 z %{Z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) u+UtvzUC
根据已有的表创建新表: b}< T<
A:create table tab_new like tab_old (使用旧表创建新表) x.CUJ^_.
B:create table tab_new as select col1,col2... from tab_old definition only |1wfLJ4--l
5、说明:删除新表 je@F:5
drop table tabname B :#5U85m
6、说明:增加一个列 W~(@*H
Alter table tabname add column col type 7Vd"k;:X
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。 Rd@34"O
7、说明:添加主键: Alter table tabname add primary key(col) VTQ V]>|
说明:删除主键: Alter table tabname drop primary key(col) A5cx!h
8、说明:创建索引:create [unique] index idxname on tabname(col....) NFw7g&1;Kp
删除索引:drop index idxname cih@:=Qy
注:索引是不可更改的,想更改必须删除重新建。 |VxEWU/
9、说明:创建视图:create view viewname as select statement ["Mq
删除视图:drop view viewname B,@geJ
10、说明:几个简单的基本的sql语句 lx$]f)%~
选择:select * from table1 where 范围 ivDmPHj{
插入:insert into table1(field1,field2) values(value1,value2) 6x|"1
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删除:delete from table1 where 范围 'RK.w^
更新:update table1 set field1=value1 where 范围 ~sj'GEhEg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! CZ"~N`
排序:select * from table1 order by field1,field2 [desc] ?,uTH
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总数:select count as totalcount from table1 X- 2 rC
求和:select sum(field1) as sumvalue from table1 a,g3/
平均:select avg(field1) as avgvalue from table1 s\i:;`l:=5
最大:select max(field1) as maxvalue from table1 3fPd|F.kF
最小:select min(field1) as minvalue from table1 r8>(ayJ,
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11、说明:几个高级查询运算词
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A: UNION 运算符 j06?Mm_c2
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。 z-};.!L^
B: EXCEPT 运算符 6Y?%G>$6
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ]Hr:|2|.
C: INTERSECT 运算符 ^*JpdmVhu
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 n${,r
注:使用运算词的几个查询结果行必须是一致的。 WeyH;P=
12、说明:使用外连接 ;^+#
A、left outer join: qYo"-D*
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。 mG4$
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 -(*<2Hy4
B:right outer join: ETU.v*HT]
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。 {p3VHd#
C:full outer join: 0kC}qru'
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。 `q
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二、提升 l{q$[/J~)
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) dQP7CP
法一:select * into b from a where 1<>1 }?[^q
法二:select top 0 * into b from a 74f3a|vx/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 0-Z
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insert into b(a, b, c) select d,e,f from b; Pf,S`Uw;
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) s&(,_34
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &%J+d"n(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. j7r! N^
4、说明:子查询(表名1:a 表名2:b) a (Q4*XH4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) =2+';Xk\
5、说明:显示文章、提交人和最后回复时间 kkWqP20q
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b w&&uk[Gh/a
6、说明:外连接查询(表名1:a 表名2:b) *;^!FBT
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .gY}}Q
7、说明:在线视图查询(表名1:a ) }{FKs!(4
select * from (SELECT a,b,c FROM a) T where t.a > 1; P$l-p'U-
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 Ce&nMgd~
select * from table1 where time between time1 and time2 )gM3,gSS
select a,b,c, from table1 where a not between 数值1 and 数值2 WKVoqp}
9、说明:in 的使用方法 zx)^!dEMM
select * from table1 where a [not] in ('值1','值2','值4','值6') Qdepzo>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 m
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5vxKkk&i4l
11、说明:四表联查问题: !%w#h0(b
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 ..... D2hEI2S
12、说明:日程安排提前五分钟提醒 bOIVe
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 g;p]lVx=>
13、说明:一条sql 语句搞定数据库分页 z3F ^OU
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 dFdll3bC
14、说明:前10条记录 e<_yr>9g"
select top 10 * form table1 where 范围 JtB"Dh
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.) D@]gc&JN[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) b1X.#pz7F
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 nq'vq]]
(select a from tableA ) except (select a from tableB) except (select a from tableC) kk`BwRh)d;
17、说明:随机取出10条数据 , $;g'z!N
select top 10 * from tablename order by newid() m]g"]U:
18、说明:随机选择记录 oECM1'=Bf
select newid() q\ihye
19、说明:删除重复记录 !sF! (u7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <9za!.(zu
20、说明:列出数据库里所有的表名 /t"p^9!^
select name from sysobjects where type='U' G'|Emu=4
21、说明:列出表里的所有的 w8~J5XS
select name from syscolumns where id=object_id('TableName') [,GXA)j
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 p)
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type b0\'JZ
显示结果: sy^k:y?
type vender pcs &p?Oo^
电脑 A 1 iU)-YFO
电脑 A 1 D+ki2UVt&
光盘 B 2 NW-l_]k
光盘 A 2 bYzBe\^3q3
手机 B 3 {d|R67~V
手机 C 3 .aRL'1xHl
23、说明:初始化表table1 U3ygFW%
TRUNCATE TABLE table1 OL+!,Y
24、说明:选择从10到15的记录 apW0(&\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [V#"7O vl
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三、技巧 ;bt@wgY
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?$O5w*
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: o]NL_SM_
if @strWhere !='' vS~y~ uU%6
begin TO\%F}m(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5io7!%
end Z&mV1dxR
else NJYx.TL
begin <`dF~
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qZ!1>`B
end \!UNale
我们可以直接写成 Y^)VHE]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &77]h%B>
2、收缩数据库 ivdw1g|)h
--重建索引 {Y5h*BD>
DBCC REINDEX my#qmI
DBCC INDEXDEFRAG Isq3YY
--收缩数据和日志 _/[n/"gn
DBCC SHRINKDB l<<G".?
DBCC SHRINKFILE 1B3,lYBM
3、压缩数据库 vOYcS$,^X%
dbcc shrinkdatabase(dbname) .js4)$W^
4、转移数据库给新用户以已存在用户权限 -;$+`<%
exec sp_change_users_login 'update_one','newname','oldname' UQ|zSalv,
go ,2>:h"^
5、检查备份集 b("JgE`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' }@'xEx
6、修复数据库 nf< <]iHf
ALTER DATABASE [dvbbs] SET SINGLE_USER SwQ.tK1p
GO <!,q:[ee5
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,8(%J3J
GO _ED1".f
ALTER DATABASE [dvbbs] SET MULTI_USER @C=, >+D
GO h3;Ij '
7、日志清除 PMZdz>>T
SET NOCOUNT ON ErC~,5dj;n
DECLARE @LogicalFileName sysname, Q}jbk9gM5
@MaxMinutes INT, f}4c#x
@NewSize INT ,8uu,,c
USE tablename -- 要操作的数据库名 ;U<)$5
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 f5a%/1?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 0:G@a&Lr
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1at$_\{.(
-- Setup / initialize Fm}O,=
DECLARE @OriginalSize int 81a&99k#
SELECT @OriginalSize = size o,) p *glO
FROM sysfiles *9^CgLF
WHERE name = @LogicalFileName f/)3b`$Wu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Pi?*rr5WZ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + KGUpXMd^Z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' v >3ctP{
FROM sysfiles rOY^w9!
WHERE name = @LogicalFileName <YL\E v/[
CREATE TABLE DummyTrans OxF\Hm)(
(DummyColumn char (8000) not null) ZNB*Azi
DECLARE @Counter INT, +2oZB]GPL
@StartTime DATETIME, \Y9=dE}
@TruncLog VARCHAR(255) ^J>28Q\S
SELECT @StartTime = GETDATE(), ~E^EF{h
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' gx[#@(
DBCC SHRINKFILE (@LogicalFileName, @NewSize) M;MD-|U
EXEC (@TruncLog) _|8"&*T^
-- Wrap the log if necessary. *Oz5I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) RA[` Cp"
AND (@OriginalSize * 8 /1024) > @NewSize !w
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BEGIN -- Outer loop. UO"8 I2rB
SELECT @Counter = 0 5d}PrYa
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "4"\tM(
BEGIN -- update CjQ_oNI
INSERT DummyTrans VALUES ('Fill Log') +:&(Ag
DELETE DummyTrans 3:Co K#
SELECT @Counter = @Counter + 1 D .Cm&
END P[P!WLr""
EXEC (@TruncLog) nE-=7S L
END glHag"(
SELECT 'Final Size of ' + db_name() + ' LOG is ' + wX 41R]pF
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !^axO
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #bu`W!p}
FROM sysfiles mKpUEJ<a
WHERE name = @LogicalFileName k5-mK{RZ
DROP TABLE DummyTrans -I=}SZ
SET NOCOUNT OFF ">fgoDQ
8、说明:更改某个表 QHs=Zh;"
exec sp_changeobjectowner 'tablename','dbo' rvE!Q=y~
9、存储更改全部表 >^J!Z~;L)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch lYw A5|+
@OldOwner as NVARCHAR(128), <Mc:Cg8>
@NewOwner as NVARCHAR(128) *7*g!
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AS \f66ipZK*
DECLARE @Name as NVARCHAR(128) g8kw|BgnL
DECLARE @Owner as NVARCHAR(128) /LSiDys
DECLARE @OwnerName as NVARCHAR(128) 66L*6O4
DECLARE curObject CURSOR FOR SgXXitg9+
select 'Name' = name, r.ajw&J2
'Owner' = user_name(uid) Y_/Kd7,\~
from sysobjects `MTOe1
where user_name(uid)=@OldOwner '&<-,1^L
order by name Zl,K#
OPEN curObject OD1ns
FETCH NEXT FROM curObject INTO @Name, @Owner [q.W!l4E
WHILE(@@FETCH_STATUS=0) qE,%$0g
BEGIN O1#rCFC|y
if @Owner=@OldOwner hChM hc
begin ;
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) [ z$J
exec sp_changeobjectowner @OwnerName, @NewOwner La9@h"
end 3al5Vu2:
-- select @name,@NewOwner,@OldOwner *fd` .}
FETCH NEXT FROM curObject INTO @Name, @Owner M.OWw#?p:_
END 5h{Hf]A
close curObject LnJ7i"Q
deallocate curObject It_yh
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GO t*}<v@,
10、SQL SERVER中直接循环写入数据 *Mp<4B
declare @i int VGvOwd)E
set @i=1 G,"$Erx
while @i<30 ^d=Z/d[
begin JR<R8+@g_
insert into test (userid) values(@i) PPq*_Cf
set @i=@i+1 ptDA))7M/
end r*p%e\ 3
小记存储过程中经常用到的本周,本月,本年函数 NX=dx&i>+
Dateadd(wk,datediff(wk,0,getdate()),-1) b&_p"8)_
Dateadd(wk,datediff(wk,0,getdate()),6) oNCDG|8z
Dateadd(mm,datediff(mm,0,getdate()),0) fGe{7p6XV*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) i'5bPW
Dateadd(yy,datediff(yy,0,getdate()),0) j_H
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6nq.~f2`
上面的SQL代码只是一个时间段 ', &MYm\
Dateadd(wk,datediff(wk,0,getdate()),-1) !< X_XA
Dateadd(wk,datediff(wk,0,getdate()),6) ?,8b-U#A1
就是表示本周时间段. $\K(EBi#G
下面的SQL的条件部分,就是查询时间段在本周范围内的: x4( fW\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) & {/u>,
而在存储过程中 <%Rr-,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Fh/C{cX9g
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =H?Nb:s