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。 ItAC=/(d
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一、基础 o+S?j*mv@
1、说明:创建数据库 F5w=tK
CREATE DATABASE database-name =[gFaB_H
2、说明:删除数据库 V:g XP1P
drop database dbname HDs8 M
3、说明:备份sql server :"+3Uk2
--- 创建 备份数据的 device *kJa$3*r
USE master 8PG&/"K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' v6T<K)S
--- 开始 备份 SNH AL F
BACKUP DATABASE pubs TO testBack P>|sCF
4、说明:创建新表 ~k ]$J|}za
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 4 %u\dTg/B
根据已有的表创建新表: #"o`'5
A:create table tab_new like tab_old (使用旧表创建新表) X8XE_VtP
B:create table tab_new as select col1,col2... from tab_old definition only 2nSz0 .
5、说明:删除新表 @,pn/[
drop table tabname H\|H]: CE
6、说明:增加一个列 Jb8%A@Z+
Alter table tabname add column col type Q:Y`^jP
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。 "m}N
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7、说明:添加主键: Alter table tabname add primary key(col) m`@~ZIa?>B
说明:删除主键: Alter table tabname drop primary key(col) 2W63/kRbU
8、说明:创建索引:create [unique] index idxname on tabname(col....) Ye[Fu/0
删除索引:drop index idxname SQJ4}w>i
注:索引是不可更改的,想更改必须删除重新建。 #*}cc
9、说明:创建视图:create view viewname as select statement rFto1m
删除视图:drop view viewname miY=xwK&
10、说明:几个简单的基本的sql语句 !Jaj2mS.N
选择:select * from table1 where 范围 (~:ip)v
插入:insert into table1(field1,field2) values(value1,value2) .5#+)] l
删除:delete from table1 where 范围 GGGz7_s
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更新:update table1 set field1=value1 where 范围 }&EdA;/o_
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uN$ <7KB"
排序:select * from table1 order by field1,field2 [desc] qp/nWGj
总数:select count as totalcount from table1 P_
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求和:select sum(field1) as sumvalue from table1 #5^S@}e
平均:select avg(field1) as avgvalue from table1 (%{!TJg ZR
最大:select max(field1) as maxvalue from table1 >5Sm.7}R
最小:select min(field1) as minvalue from table1 Q1DiEg
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11、说明:几个高级查询运算词 }y%mG&KSz
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A: UNION 运算符 ?"p.Gy)
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 biHZyUJ
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。 BM02k\%
C: INTERSECT 运算符 =>xyJ->R
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。 d s}E|Q
注:使用运算词的几个查询结果行必须是一致的。 e.;B?0QrV
12、说明:使用外连接 iUf?MDE
A、left outer join: Ntpw(E<$f
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ^O3p:X4u
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |b|bL 7nx
B:right outer join: :2;c@ uj
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 c+UZ UgP
C:full outer join: zY&/lWW._
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 I -V=Z:
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二、提升 ^<Sy{KY
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) I$I',x5Z
法一:select * into b from a where 1<>1 [}"m4+
法二:select top 0 * into b from a XJ?zP=UK
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =o4McV}
insert into b(a, b, c) select d,e,f from b; hDTM\>.c;s
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) G}'\
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 nD{{/_"'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]Q{MF- EKj
4、说明:子查询(表名1:a 表名2:b) 51!#m|
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) <+ckE2j
5、说明:显示文章、提交人和最后回复时间 5Ja[p~^L
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b '\Uy;,tu /
6、说明:外连接查询(表名1:a 表名2:b) WL<f!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c PE2O$:b\
7、说明:在线视图查询(表名1:a ) Kd3EZo.
select * from (SELECT a,b,c FROM a) T where t.a > 1; HhB'
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 J-~:W~Qx4N
select * from table1 where time between time1 and time2 h.aXW]]}(P
select a,b,c, from table1 where a not between 数值1 and 数值2 r59BBW)M
9、说明:in 的使用方法 U5H5QW +
select * from table1 where a [not] in ('值1','值2','值4','值6') qmbhx9V
10、说明:两张关联表,删除主表中已经在副表中没有的信息 r} a,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +J:wAmY4
11、说明:四表联查问题: _z&H O
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... TiSV`V q
12、说明:日程安排提前五分钟提醒 -VZ?
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8?$XT
13、说明:一条sql 语句搞定数据库分页 Opf^#6'mq
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 X"v)9p
14、说明:前10条记录 dqw0ns.2
select top 10 * form table1 where 范围 mUwGr_)wj
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.) X%Ta?(9|.^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w;V+)r?w
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 ^e1mK4`
(select a from tableA ) except (select a from tableB) except (select a from tableC) #(r1b'jfP
17、说明:随机取出10条数据 lC=T{rR
select top 10 * from tablename order by newid() p~Mw^SN'
18、说明:随机选择记录 1tFx
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select newid() u!I=|1s
19、说明:删除重复记录 AF"XsEt.e
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +(##B pC
20、说明:列出数据库里所有的表名 wRQMuFGY
select name from sysobjects where type='U' 6G?7>M
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') =~{W;VZt'
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。 h2ou ]
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 + :k"{I
显示结果: -|/*S]6kK
type vender pcs 0J1&6b
电脑 A 1 Hc-Ke1+
电脑 A 1 r$;u4FR
光盘 B 2 MK, $#
光盘 A 2 kr5'a:F)
手机 B 3 %CG=mTP
手机 C 3 X6EnC57
23、说明:初始化表table1 5@{~830
TRUNCATE TABLE table1 KvuM{UI5
24、说明:选择从10到15的记录 B7nm7[V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 9I*`~il>{
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三、技巧 ,\0>d}eh!
1、1=1,1=2的使用,在SQL语句组合时用的较多 F;)qM|7
"where 1=1" 是表示选择全部 "where 1=2"全部不选, p (x<h
如: 3Cl&1K #5
if @strWhere !='' _qq>-{-Ym
begin ^97\TmzP{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere l =^ ^l`
end ]YwvwmZ
else D>"!7+t|@a
begin iLJBiZ+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ox"SQ`nSj'
end =1% <
我们可以直接写成 r*W&SU9Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &W-1W99auE
2、收缩数据库 S *K0OUq
--重建索引 qiyJ4^1
DBCC REINDEX Pxe7 \e
DBCC INDEXDEFRAG yI_MYL[
--收缩数据和日志 ]d50J@W
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DBCC SHRINKDB (,2U?p
DBCC SHRINKFILE _}:#T8h
3、压缩数据库 -bQi4
dbcc shrinkdatabase(dbname) Zi ;7.P qL
4、转移数据库给新用户以已存在用户权限 VyxX5Lrj
exec sp_change_users_login 'update_one','newname','oldname' A=pyaU`aE
go TvwkeOS#}7
5、检查备份集 qM:*!Aq0g
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;&]oV`Ib
6、修复数据库 z%Ivc*x5
ALTER DATABASE [dvbbs] SET SINGLE_USER U&SgB[QHO
GO )VFS&|#\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK u_X(c'aE;
GO td\'BV
ALTER DATABASE [dvbbs] SET MULTI_USER gl!F)RdH
GO hwd{^
7、日志清除 x_.}C%
SET NOCOUNT ON T6Ks]6m_
DECLARE @LogicalFileName sysname, CeW}zkcT
@MaxMinutes INT, l08JL
@NewSize INT Z6_E/S
USE tablename -- 要操作的数据库名 nO .:f
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 K.: :P84m;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Tlz~o[`&
@NewSize = 1 -- 你想设定的日志文件的大小(M) r>x>aJ
-- Setup / initialize 38gEto#q
DECLARE @OriginalSize int nSeb?|$D 6
SELECT @OriginalSize = size
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FROM sysfiles F`JW&r\
WHERE name = @LogicalFileName qJT|om
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + -)Y[t Z^*`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #EX NS r
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' yU< "tg E
FROM sysfiles v!%VH?cA8
WHERE name = @LogicalFileName #kPsg9Y
CREATE TABLE DummyTrans @w@ `-1
(DummyColumn char (8000) not null) @1iH4RE*
DECLARE @Counter INT, \6K1Z!*;
@StartTime DATETIME, @RFJe$%
@TruncLog VARCHAR(255) u13v@<HGc
SELECT @StartTime = GETDATE(), 4#2iq@s
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5WU?Km
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7G 5VwO
EXEC (@TruncLog) $'
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-- Wrap the log if necessary. Ts
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired QeipfK+me
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) x$/:%"E
AND (@OriginalSize * 8 /1024) > @NewSize C9"yu&l
BEGIN -- Outer loop. |A19IXZ\
SELECT @Counter = 0 a
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) xzOM\Nq?O
BEGIN -- update g%T` 6dvT
INSERT DummyTrans VALUES ('Fill Log') c-bTf$6}
DELETE DummyTrans R:t
SELECT @Counter = @Counter + 1 /H<tv5mXJ
END ps@{1Rn1
EXEC (@TruncLog) "IKbb7x
END C#D8
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + &1,{.:@e
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + WiCJhVF3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Qvhz$W[P>
FROM sysfiles (ixlFGvEq
WHERE name = @LogicalFileName TM^.y
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DROP TABLE DummyTrans b<"LUM*;
SET NOCOUNT OFF Jqgo\r%`
8、说明:更改某个表 [gxH,=Pb
exec sp_changeobjectowner 'tablename','dbo' N"&qy3F
9、存储更改全部表 pm k;5 d
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 37nGFH`K2m
@OldOwner as NVARCHAR(128), G=qT{c8Q
@NewOwner as NVARCHAR(128) OysO55 i
AS =y WHm
DECLARE @Name as NVARCHAR(128) f`"@7-N
DECLARE @Owner as NVARCHAR(128) p-,(P+Np
DECLARE @OwnerName as NVARCHAR(128) `]4bH,%~
DECLARE curObject CURSOR FOR 7Hzv-s
select 'Name' = name, AN
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'Owner' = user_name(uid) L(w?.)E
from sysobjects [pYjH+<
where user_name(uid)=@OldOwner px=r~8M9}
order by name 6T ,'Oz
OPEN curObject d2[R{eNX=
FETCH NEXT FROM curObject INTO @Name, @Owner ZRLS3*`
WHILE(@@FETCH_STATUS=0) '?dT<w=Y&
BEGIN w@&(=C
if @Owner=@OldOwner AG(Gtvw
begin 8u4Fag Q,
set @OwnerName = @OldOwner + '.' + rtrim(@Name) lko
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exec sp_changeobjectowner @OwnerName, @NewOwner e.?;mD
end #5}v?
-- select @name,@NewOwner,@OldOwner 7bC)Co#:
FETCH NEXT FROM curObject INTO @Name, @Owner { K*
END XD$;K$_7
close curObject ?N(opggiD
deallocate curObject ;J&9l
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GO <A@qN95m
10、SQL SERVER中直接循环写入数据 .YxcXe3#
declare @i int '(!U5j
set @i=1 ;iTZzmB
while @i<30 19 <Lgr
begin +N:=|u.g
insert into test (userid) values(@i) eL{6;.C
set @i=@i+1 LQ3J$N
end ^muPjM+D
小记存储过程中经常用到的本周,本月,本年函数 |tqYRWn0
Dateadd(wk,datediff(wk,0,getdate()),-1) NG?- dkD
Dateadd(wk,datediff(wk,0,getdate()),6) bbxo!K
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Dateadd(mm,datediff(mm,0,getdate()),0) J\c\Ar:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 2!;U.+(
Dateadd(yy,datediff(yy,0,getdate()),0) r0/o{Y|l6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) J1gLT $
上面的SQL代码只是一个时间段 ,%EGM+
Dateadd(wk,datediff(wk,0,getdate()),-1) y(h"0A1lW
Dateadd(wk,datediff(wk,0,getdate()),6) R"V^%z;8o
就是表示本周时间段. APM!xX=N
下面的SQL的条件部分,就是查询时间段在本周范围内的: )2mvW1M=7;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -/3D0`R
而在存储过程中 Yo;Mexo!
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) l~c# X3E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) pIP^/H