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。 Onou:kmf1
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一、基础 *{5/" H5
1、说明:创建数据库 ;=k{[g 'gv
CREATE DATABASE database-name -yb7s2o
2、说明:删除数据库 U"oHPK3"TA
drop database dbname )rlkQ'DN
3、说明:备份sql server QpRk5NeLe
--- 创建 备份数据的 device #_UP}G$
USE master *ae)<l3v
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' lY2~{Y|4s
--- 开始 备份 u J]uz%
BACKUP DATABASE pubs TO testBack 2%J] })
4、说明:创建新表 R&g&BF
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h7@%}<%
根据已有的表创建新表: RGkV%u^
A:create table tab_new like tab_old (使用旧表创建新表) .J8 gW
B:create table tab_new as select col1,col2... from tab_old definition only :Nwv&+
5、说明:删除新表 Q7{{r&|t&
drop table tabname aof'shS8
6、说明:增加一个列 b5I 8jPj4c
Alter table tabname add column col type gm=C0Sp?
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。 wy{sS}
7、说明:添加主键: Alter table tabname add primary key(col) :ln?PT
说明:删除主键: Alter table tabname drop primary key(col) R3.w")6
8、说明:创建索引:create [unique] index idxname on tabname(col....) f`_{SU"3
删除索引:drop index idxname f9
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注:索引是不可更改的,想更改必须删除重新建。 w'XSkI_ay
9、说明:创建视图:create view viewname as select statement {d]B+'
删除视图:drop view viewname <:T/hm$
10、说明:几个简单的基本的sql语句 [>\e@ =
选择:select * from table1 where 范围 adRIg:2
插入:insert into table1(field1,field2) values(value1,value2) c5:0`~5Fn
删除:delete from table1 where 范围 [2>zaag
更新:update table1 set field1=value1 where 范围 9I$}=&"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! :eT\XtxM~{
排序:select * from table1 order by field1,field2 [desc] UEt78eN
总数:select count as totalcount from table1 -#R`n'/
求和:select sum(field1) as sumvalue from table1 t0kZFU
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 ^:mKTiA-
最小:select min(field1) as minvalue from table1 %M/L/_d
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11、说明:几个高级查询运算词 Cbl>eKw
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A: UNION 运算符 )EQI>1_
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 CfD4m,6
B: EXCEPT 运算符 FP7N^HVBG=
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 #<U@SMv
C: INTERSECT 运算符 9ZR"Lo>3e+
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 b$_qG6)IJO
注:使用运算词的几个查询结果行必须是一致的。 p@O,-&/D
12、说明:使用外连接 6ecx!uc$
A、left outer join: )8'v@8;-
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。 vILB$%I
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c UH;bg}=8
B:right outer join: a`]ZyG*P
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 -[pfLo
C:full outer join: ^eefR5^_w
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 G#@#j]8
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二、提升 w7Mh8'P54
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |9Yx`_DF
法一:select * into b from a where 1<>1 l-!"
法二:select top 0 * into b from a KK]R@{ r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &5sPw^{,H
insert into b(a, b, c) select d,e,f from b; dM19;R@4
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) .y_ ~mr&d
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TiZ
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4、说明:子查询(表名1:a 表名2:b) k`]76C7
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Zy{hYHQ
5、说明:显示文章、提交人和最后回复时间 k6Vs#K7a
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8wZ
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6、说明:外连接查询(表名1:a 表名2:b) (2"4PU8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -*Qg^1]i+
7、说明:在线视图查询(表名1:a ) 1=E}X5
select * from (SELECT a,b,c FROM a) T where t.a > 1; ,?Vxcr
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 *UJB*r
select * from table1 where time between time1 and time2 45iO2W uur
select a,b,c, from table1 where a not between 数值1 and 数值2 n<HF]
9、说明:in 的使用方法 yp@cn(:~
select * from table1 where a [not] in ('值1','值2','值4','值6') \IzZJGi
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9$VdYw7D
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7lJ8<EP9
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11、说明:四表联查问题: V~5vR`}
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 ..... uC#]F@
12、说明:日程安排提前五分钟提醒 7~ZG"^k
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 SrOv*
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13、说明:一条sql 语句搞定数据库分页 kkj@!1q(wO
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 >yqEXx5{
14、说明:前10条记录 Wf%)::G*uR
select top 10 * form table1 where 范围 (Ia:>ocE0
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.) HM"(cB(n`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) a8%T*mk(
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 +|K,\
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(select a from tableA ) except (select a from tableB) except (select a from tableC) |Xd&aQ
17、说明:随机取出10条数据 Do^yer~
select top 10 * from tablename order by newid() -xJ\/"A
18、说明:随机选择记录 upJy,|5
select newid() }v?l0Gk(
19、说明:删除重复记录 #^ .G^d(=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 IBNb!mPu%
select name from sysobjects where type='U' NcX-*o
21、说明:列出表里的所有的 L;b-=mF
select name from syscolumns where id=object_id('TableName') U~c9PqjZ
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。 R iV]SgV9
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 _+}hId
显示结果: G4#Yz6O
type vender pcs /^&$ma\
电脑 A 1 /jq"r-S"
电脑 A 1 !}1l8Y
光盘 B 2 y] Cx[
光盘 A 2 ]#q$i[Y
手机 B 3 Aqg$q* Y
手机 C 3 CPP9=CoR37
23、说明:初始化表table1 SL^%Zh/~
TRUNCATE TABLE table1 kjQI=:i=
24、说明:选择从10到15的记录 AP=SCq;
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc cmaha%3d
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三、技巧 y4!fu<[i
1、1=1,1=2的使用,在SQL语句组合时用的较多 o5Knot)Oy
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [r'hX#
如: +s [_
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if @strWhere !='' soKR*gJ,
begin a{?>F&vnU
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere fKua om9
end ypfjF@OT
else W>P :EI1
begin 8@T0]vH&
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l|9'l[}&
end f\~w!-
我们可以直接写成 xu;^F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PM {L}tEQ
2、收缩数据库 :X*uE^bH
--重建索引 l?;ReK.r
DBCC REINDEX f9n4/(Cy
DBCC INDEXDEFRAG >4#\ U!
--收缩数据和日志 u9+)jN<Yh
DBCC SHRINKDB jar?"o
DBCC SHRINKFILE mj9]M?]
3、压缩数据库 :4COPUBpPV
dbcc shrinkdatabase(dbname) \D[~54
4、转移数据库给新用户以已存在用户权限 L;KLmxy#
exec sp_change_users_login 'update_one','newname','oldname' 9@*4^Ks p
go icK U)
5、检查备份集 ?C6`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' \OK}DhY#
6、修复数据库 xlW>3'uHfa
ALTER DATABASE [dvbbs] SET SINGLE_USER Me;Nn$'%
GO lPl JL`e
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK }yCgd 5+_
GO i l%9j
ALTER DATABASE [dvbbs] SET MULTI_USER _b=})**
GO x6=tS
7、日志清除 kaCn@$
SET NOCOUNT ON _g"su#
DECLARE @LogicalFileName sysname, b|`
@MaxMinutes INT, uQWd`7
@NewSize INT ^^)\|kW?
USE tablename -- 要操作的数据库名 $>%zNq-F
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 6(HJYa
@MaxMinutes = 10, -- Limit on time allowed to wrap log. L+)mZb&
@NewSize = 1 -- 你想设定的日志文件的大小(M) qZSW5lC0
-- Setup / initialize x/92],.Mz
DECLARE @OriginalSize int 9AQ2FD
SELECT @OriginalSize = size Aq/wa6^%
FROM sysfiles WS$~o*Z8
WHERE name = @LogicalFileName m(WVxVB
SELECT 'Original Size of ' + db_name() + ' LOG is ' + =E8Kacu%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \<y#$:4r<8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z&[[4[
FROM sysfiles #8bI4J{dE
WHERE name = @LogicalFileName GuJIN"P]
CREATE TABLE DummyTrans ;Y(~'KF
(DummyColumn char (8000) not null) 8@I.\u)0
DECLARE @Counter INT, +
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@StartTime DATETIME, yXc@i)9w3
@TruncLog VARCHAR(255) An
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SELECT @StartTime = GETDATE(), iWn7vv/t
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0+S'i82=M
DBCC SHRINKFILE (@LogicalFileName, @NewSize) z7lbb*Xe
EXEC (@TruncLog) nSU7,K`PM
-- Wrap the log if necessary. W@FGU
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired c<qJs-C4;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) k${F7I(Tb
AND (@OriginalSize * 8 /1024) > @NewSize #Cz:l|\ i
BEGIN -- Outer loop. VH.}}RS%
SELECT @Counter = 0 #DHeEE
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) niM(0p
BEGIN -- update t]pJt
INSERT DummyTrans VALUES ('Fill Log') &44?k:
DELETE DummyTrans ]^l-k@
SELECT @Counter = @Counter + 1 mDU-;3OqF
END qk(u5Z
EXEC (@TruncLog) * (<3 oIRS
END rB5+~
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + lnnt b3q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~9+\
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k+cHx799
FROM sysfiles aeF^&F0
WHERE name = @LogicalFileName 7kidPAhY
DROP TABLE DummyTrans *yA.D?
SET NOCOUNT OFF Bk~M ^AK@~
8、说明:更改某个表 .'N#qs_
exec sp_changeobjectowner 'tablename','dbo' 2E3x=
9、存储更改全部表 G{oM2`c'#8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ZbcpE~<a
@OldOwner as NVARCHAR(128), cY*lsBo
@NewOwner as NVARCHAR(128) J7rfHhz
AS cV)~%e/
DECLARE @Name as NVARCHAR(128) &]/.=J
DECLARE @Owner as NVARCHAR(128) <3Hu(Jx<O
DECLARE @OwnerName as NVARCHAR(128) iD9hqiX&
DECLARE curObject CURSOR FOR MMUw+jM4
select 'Name' = name, ::kpAE]
'Owner' = user_name(uid) JTB5#S4W
from sysobjects }L*cP;m#
where user_name(uid)=@OldOwner KHXnB
order by name :J+GodW
OPEN curObject K3t^y`z
FETCH NEXT FROM curObject INTO @Name, @Owner r7p>`>_Q\
WHILE(@@FETCH_STATUS=0) .](s\6'
BEGIN D$c4's`5
if @Owner=@OldOwner S-+^L|
begin $rE_rZ+]="
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1YMu\(
exec sp_changeobjectowner @OwnerName, @NewOwner x;*KRO
end Ss7XjWP.}
-- select @name,@NewOwner,@OldOwner *,DBRJ_*7
FETCH NEXT FROM curObject INTO @Name, @Owner !b+Kasss9
END 1{S"
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close curObject jVu3 !{}
deallocate curObject ?2b9N ~
GO [VP~~*b
10、SQL SERVER中直接循环写入数据 !xK`:[B
declare @i int e: :H1V
set @i=1 BK]q^.7+:
while @i<30 nEm+cHHo?
begin vd<"
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insert into test (userid) values(@i) Ws`P(WHm
set @i=@i+1 ,*Yu~4
end 07+Qai-]
小记存储过程中经常用到的本周,本月,本年函数 <kmn3w,vi
Dateadd(wk,datediff(wk,0,getdate()),-1) w~g)Dz2G
Dateadd(wk,datediff(wk,0,getdate()),6) `4 A%BKYB
Dateadd(mm,datediff(mm,0,getdate()),0) KmkPq]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ToVm]zPOUt
Dateadd(yy,datediff(yy,0,getdate()),0) _\LAWQ|M4[
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) vH#^ |u
上面的SQL代码只是一个时间段 Ofg-gCF8
Dateadd(wk,datediff(wk,0,getdate()),-1) +d736lLe%
Dateadd(wk,datediff(wk,0,getdate()),6) Sc*O_c3D
就是表示本周时间段. Rj=xn(@d
下面的SQL的条件部分,就是查询时间段在本周范围内的: pJ5Sxgv{;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) DFt1{qS8@u
而在存储过程中 K(HP PM\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ,tL<?6_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qyuU