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。 8}[).d160
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一、基础 do%&m]#;
1、说明:创建数据库 IPk4
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CREATE DATABASE database-name .H|-_~Yx|
2、说明:删除数据库 *|0 -~u%q
drop database dbname j.Hf/vi`z
3、说明:备份sql server D-c4EV
--- 创建 备份数据的 device #R"*c
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USE master rsQtMtS2
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -"`=1l
--- 开始 备份 3mgD(,(^
BACKUP DATABASE pubs TO testBack >%G1"d?j
4、说明:创建新表 H)?z
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) M7T5
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根据已有的表创建新表: s*[bFJwN
A:create table tab_new like tab_old (使用旧表创建新表) 8Wx=p#_
B:create table tab_new as select col1,col2... from tab_old definition only I0-MRU~[K
5、说明:删除新表 %{|p j
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drop table tabname \<' ?8ri#
6、说明:增加一个列 DF= *_,2/
Alter table tabname add column col type CY1Z'
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。 .3;;;K9a~]
7、说明:添加主键: Alter table tabname add primary key(col) paK2xX8E
说明:删除主键: Alter table tabname drop primary key(col) *T/']t
8、说明:创建索引:create [unique] index idxname on tabname(col....) #4PN"o@
删除索引:drop index idxname X,
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注:索引是不可更改的,想更改必须删除重新建。 6'/ #+,d'
9、说明:创建视图:create view viewname as select statement D^O@'zP=At
删除视图:drop view viewname y0#2m6u
10、说明:几个简单的基本的sql语句 \85i+q:LuA
选择:select * from table1 where 范围 gJXaPJA{
插入:insert into table1(field1,field2) values(value1,value2) +rd+0 `}C
删除:delete from table1 where 范围 AKC`TA*E
更新:update table1 set field1=value1 where 范围 \~W'v3:W
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8=l%5r^cq
排序:select * from table1 order by field1,field2 [desc] kj_c%T
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总数:select count as totalcount from table1 Upe%rC(
求和:select sum(field1) as sumvalue from table1 $mI Loy
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平均:select avg(field1) as avgvalue from table1 ! mHO$bQ"
最大:select max(field1) as maxvalue from table1 fVlB=8DNk&
最小:select min(field1) as minvalue from table1 5+'<R8{:,
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11、说明:几个高级查询运算词 ;I}fBZ3
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A: UNION 运算符 CZ;6@{ o
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。 C]6O!Pb0
B: EXCEPT 运算符 )e{aN+
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。 Hka2
C: INTERSECT 运算符 5O%{{J
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。 (>Em^(&
注:使用运算词的几个查询结果行必须是一致的。 I,tud!p`
12、说明:使用外连接 {FkF
A、left outer join: Psf#c:*_)
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。 kmW4:EA%
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 Y4-t7UlS;
B:right outer join: J5qZFD
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。 -f .,tM=
C:full outer join: *w&e\i|7
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。 ;uJMG
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二、提升 zPO9!?7|
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) V!Uc(
法一:select * into b from a where 1<>1 6m93puY`7
法二:select top 0 * into b from a &
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) By|4m
insert into b(a, b, c) select d,e,f from b; .Mbz3;i0
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) ?< +WG/(d
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 COlqcq'qAu
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *@5 @,=d
4、说明:子查询(表名1:a 表名2:b) 9;{CIMg&
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) as|<}:V
5、说明:显示文章、提交人和最后回复时间 qX%_uOw:%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 1zv'.uu.,
6、说明:外连接查询(表名1:a 表名2:b) :;}P*T*PU
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?}oFg#m-<L
7、说明:在线视图查询(表名1:a ) ]^E?;1$f?
select * from (SELECT a,b,c FROM a) T where t.a > 1; la!~\wpa
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 dPlV>IM$z
select * from table1 where time between time1 and time2 }vuO$j
select a,b,c, from table1 where a not between 数值1 and 数值2 CJY$G}rk
9、说明:in 的使用方法 FrS]|=LJhX
select * from table1 where a [not] in ('值1','值2','值4','值6') Ui~>SN>s
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @"A4$`Xi3
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ?s01@f#
11、说明:四表联查问题: [,Gg^*umS
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... (QEG4&9
12、说明:日程安排提前五分钟提醒 6x`t{g]f,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 QRUz`|U
13、说明:一条sql 语句搞定数据库分页 -w2/w@&
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 J1k>07}|
14、说明:前10条记录 K-v#.e4
select top 10 * form table1 where 范围 D*jM1w_`
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) pi(m7Ci"
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Sjqpec8
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Lbgi7|&
(select a from tableA ) except (select a from tableB) except (select a from tableC) Wr
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17、说明:随机取出10条数据 p K*TE5]
select top 10 * from tablename order by newid() Q,g\
18、说明:随机选择记录 dO'(2J8
select newid() ytImB`'\
19、说明:删除重复记录 5m@V#2^P
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?<!|
20、说明:列出数据库里所有的表名 oH@78D0A
select name from sysobjects where type='U' !$JT e
21、说明:列出表里的所有的 C%u28|
select name from syscolumns where id=object_id('TableName') KlEpzJ98
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。 7CysfBF0g
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 -7ep{p-
显示结果: sJZiI}Xc
type vender pcs G|Ti4_w
电脑 A 1 9up3[F$
电脑 A 1 t@(HF-4~=
光盘 B 2 Rcuz(yS8
光盘 A 2 1MFbQs^
手机 B 3 -).C
手机 C 3 )0`C@um
23、说明:初始化表table1 hN_]6,<\
TRUNCATE TABLE table1 .-zom~N-?
24、说明:选择从10到15的记录 &oNAv-m^GD
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Z,gk|M3.
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三、技巧 ).O)p9
1、1=1,1=2的使用,在SQL语句组合时用的较多 }MySaL>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Gv&V|7-f0
如: P \I|,
if @strWhere !='' P55fL-vo|}
begin }>\C{ClI
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere kh<2BOV
end F4QVAOM]U
else :jf3HG
begin kJU2C=m@e2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' " bG2:
end PT
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我们可以直接写成 G@0&8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere sOY:e/_F
2、收缩数据库 +@UV?"d
--重建索引 _c07}aQ ],
DBCC REINDEX (FV >m
DBCC INDEXDEFRAG (7Qo
--收缩数据和日志 hH.G#-JO
DBCC SHRINKDB BtZ yn7a
DBCC SHRINKFILE l (o~-i\M
3、压缩数据库 0RfZEG)
dbcc shrinkdatabase(dbname) u*R_\*j@
4、转移数据库给新用户以已存在用户权限 \V:^h[ad
exec sp_change_users_login 'update_one','newname','oldname' z:O8Ls^\T
go >_}
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5、检查备份集 }H2R3icE
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qs6aB0ln
6、修复数据库 3|7QUld
ALTER DATABASE [dvbbs] SET SINGLE_USER %<5'=t'|-U
GO 4i bc
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK xw%0>K[
GO {g6%(X\r.r
ALTER DATABASE [dvbbs] SET MULTI_USER x-c"%Z|
GO bt *k.=p
7、日志清除 -j(6;9"7]|
SET NOCOUNT ON A&{Nh` q
DECLARE @LogicalFileName sysname, ~&O%N
@MaxMinutes INT, =N@t'fOr
@NewSize INT PF2nLb2-
USE tablename -- 要操作的数据库名 G$PE}%X
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 k)u[0}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =Qq+4F)MD
@NewSize = 1 -- 你想设定的日志文件的大小(M) IV-{ve6
-- Setup / initialize 6@f-Glwg
DECLARE @OriginalSize int & kIFcd@
SELECT @OriginalSize = size :&Nbw
FROM sysfiles p_ =z#
WHERE name = @LogicalFileName 6*?F @D2&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + $>gFf}#C
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + E^PB)D(.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' eyaNs{TV
FROM sysfiles POW>~Tof1
WHERE name = @LogicalFileName QJNFA}*>
CREATE TABLE DummyTrans mOSv9w#,
(DummyColumn char (8000) not null) 4Hg9N}
DECLARE @Counter INT, kza5ab
@StartTime DATETIME, ;<5q]/IHK
@TruncLog VARCHAR(255) R]dg_Da
SELECT @StartTime = GETDATE(), [lAp62i5
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' wr4:Go`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) NI5``BwpO
EXEC (@TruncLog) n%-0V>
-- Wrap the log if necessary. E]6
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0V]s:S
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l%ZhA=TKQ
AND (@OriginalSize * 8 /1024) > @NewSize tkhCw/
BEGIN -- Outer loop. IID5c"
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SELECT @Counter = 0 )Z$!PqRw@u
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 67TwPvh
BEGIN -- update >/\'zi]L
INSERT DummyTrans VALUES ('Fill Log') Si,6o!0k
DELETE DummyTrans 'yth'[
SELECT @Counter = @Counter + 1 B *vM0
END $(9U @N9E
EXEC (@TruncLog) !W0v >p
END \jA~9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + +"(jjxJm
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + pp2~Meg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /(T?j!nPE
FROM sysfiles S'14hk<
WHERE name = @LogicalFileName Qd6F H2Pl
DROP TABLE DummyTrans WHI`/FM
SET NOCOUNT OFF +V+a4lU14
8、说明:更改某个表 /=h` L,
exec sp_changeobjectowner 'tablename','dbo' p'fYULYE
9、存储更改全部表 {$r[5%L\H
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), F?cK-.
@NewOwner as NVARCHAR(128) }Lv;!
AS DMS!a$4
DECLARE @Name as NVARCHAR(128) *H122njH+T
DECLARE @Owner as NVARCHAR(128) D0Cy^_
DECLARE @OwnerName as NVARCHAR(128) S$3JMFA
DECLARE curObject CURSOR FOR 6RM/GM
select 'Name' = name, Ie^l~Gb
'Owner' = user_name(uid) 9kojLqCT
from sysobjects 7KPwQ?SjT
where user_name(uid)=@OldOwner 3F0 N^)@
order by name V1?]|HTQcT
OPEN curObject G
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FETCH NEXT FROM curObject INTO @Name, @Owner ca}2TT&t
WHILE(@@FETCH_STATUS=0) C7vxw-o|&p
BEGIN !c-*O<Y
if @Owner=@OldOwner fV:83|eQ
begin .o8t+X'G
set @OwnerName = @OldOwner + '.' + rtrim(@Name) X|[`P<'N<
exec sp_changeobjectowner @OwnerName, @NewOwner iUwzs&frd
end IAEAhqp
-- select @name,@NewOwner,@OldOwner nie% eC&U
FETCH NEXT FROM curObject INTO @Name, @Owner 2(nlJ7R
END :!/8Hv
close curObject bfO=;S]b!
deallocate curObject `kr?j:g
GO B:QHwzd
10、SQL SERVER中直接循环写入数据 BD-AI
declare @i int Q^I\cAIB
set @i=1 a6H%5N
while @i<30 CJ%I51F`X
begin
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insert into test (userid) values(@i) |M_UQQAB|
set @i=@i+1 8D].MI^
end <1pEwI~
小记存储过程中经常用到的本周,本月,本年函数 +)?J#g
Dateadd(wk,datediff(wk,0,getdate()),-1) fQ98(+6
Dateadd(wk,datediff(wk,0,getdate()),6) B;WCTMy}
Dateadd(mm,datediff(mm,0,getdate()),0) q9NoI(]e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) d1kJRJ
Dateadd(yy,datediff(yy,0,getdate()),0) f X)#=c|5
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Wvqhl
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上面的SQL代码只是一个时间段 Hefg[$m
Dateadd(wk,datediff(wk,0,getdate()),-1) LF7SS;&~f
Dateadd(wk,datediff(wk,0,getdate()),6) Gc!x|V;T
就是表示本周时间段. _~pbqa,
下面的SQL的条件部分,就是查询时间段在本周范围内的: 5PW^j\G-f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rGkyGz8>
而在存储过程中 =mGez )T5\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) uGt-l4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) T>GM%^h,7-