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。 i%8&g2
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一、基础 H>iZVE
1、说明:创建数据库 |7x^@i9w
CREATE DATABASE database-name 'LLx$y.Ei[
2、说明:删除数据库 RgA4@J#
drop database dbname >8O=^7
3、说明:备份sql server [#'_@zZz
--- 创建 备份数据的 device z.HNb$;
USE master [+,U0OV,
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <9tG_
--- 开始 备份 'TsZuZW]
BACKUP DATABASE pubs TO testBack 1>x@1Mo+K
4、说明:创建新表 VDjIs UUX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) =e-aZ0P
根据已有的表创建新表: ,nRwwFd.
A:create table tab_new like tab_old (使用旧表创建新表) pY>-N
B:create table tab_new as select col1,col2... from tab_old definition only [<a%\:c m4
5、说明:删除新表 VhI IW"1
drop table tabname 7d8qs%nA
6、说明:增加一个列 +u:OAsR
Alter table tabname add column col type |0R%!v(,
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。 KqUSTR1e[
7、说明:添加主键: Alter table tabname add primary key(col) dS_)ll.6z
说明:删除主键: Alter table tabname drop primary key(col) &\`a5[
8、说明:创建索引:create [unique] index idxname on tabname(col....) ||ZufFO
删除索引:drop index idxname Rn_W|"
注:索引是不可更改的,想更改必须删除重新建。 tF g'RV{
9、说明:创建视图:create view viewname as select statement u4M2Ec
删除视图:drop view viewname xYVjUb(,X
10、说明:几个简单的基本的sql语句 7+hF;
选择:select * from table1 where 范围 C*6)Ut '
插入:insert into table1(field1,field2) values(value1,value2) _JIUds5
删除:delete from table1 where 范围 n9fA!Wic
更新:update table1 set field1=value1 where 范围 %R*vSRG/U
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yP9wYF^A\
排序:select * from table1 order by field1,field2 [desc] 9AddF*B
总数:select count as totalcount from table1 o``>sBZOq
求和:select sum(field1) as sumvalue from table1 nC.2./OwMf
平均:select avg(field1) as avgvalue from table1 (s@tU>4U
最大:select max(field1) as maxvalue from table1 .C;_4jE
最小:select min(field1) as minvalue from table1 (yAvDyJOn
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11、说明:几个高级查询运算词 rbuL@=S@*
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A: UNION 运算符 |}p}`Mb)a
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。 VMye5 P
B: EXCEPT 运算符 z vb}p
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。 ]baaOD$Z
C: INTERSECT 运算符 xgT~b9
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 O:^LQ
注:使用运算词的几个查询结果行必须是一致的。 i$^B-
12、说明:使用外连接 V>j hGf
A、left outer join: :{WrS
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。 t-7U1B}=<C
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 .F$|j1y
B:right outer join: jy(+
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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。 W6Aj<{\F
C:full outer join: I`'a'
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。 <k\H`P
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二、提升 6%\Q*r*N
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) jWK@NXMH
法一:select * into b from a where 1<>1 }\u% )uZ
法二:select top 0 * into b from a <ql w+RVt
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) T~o{woq}g
insert into b(a, b, c) select d,e,f from b; Gl8&FrR
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%0d\{@a
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 WfDX"rA
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "rx^M*"
4、说明:子查询(表名1:a 表名2:b) jH&_E'XMX
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) y5/'!L)g
5、说明:显示文章、提交人和最后回复时间 R{)
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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 )jlP
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6、说明:外连接查询(表名1:a 表名2:b) 2T@L{ ql
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6
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7、说明:在线视图查询(表名1:a ) 6hM]%
select * from (SELECT a,b,c FROM a) T where t.a > 1; zRV!(Y
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 V@v1a@=W
select * from table1 where time between time1 and time2 e`Co,>W/
select a,b,c, from table1 where a not between 数值1 and 数值2 $Eio$TI
9、说明:in 的使用方法 3T|Y}
select * from table1 where a [not] in ('值1','值2','值4','值6') `s`C{|wv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7}?k^x,1
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l@N;sI<O-
11、说明:四表联查问题: bR`rT4.F
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 ..... L\ }Pzxn
12、说明:日程安排提前五分钟提醒 hI|/>4<
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 -]Q(~'a
13、说明:一条sql 语句搞定数据库分页 T~%H%O(F
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 .!(,$'(@=
14、说明:前10条记录 dh^+l;!L
select top 10 * form table1 where 范围 {[2tG U9
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) "F-Y^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) !TP6=ks
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 )?w&oIj5
(select a from tableA ) except (select a from tableB) except (select a from tableC) e=t<H"&
17、说明:随机取出10条数据 U_}7d"<| ?
select top 10 * from tablename order by newid() _+twqi
18、说明:随机选择记录 r8uqcKfU
select newid() ~{L.f94N
19、说明:删除重复记录 8p (!]^z
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [kbC'Eh*
20、说明:列出数据库里所有的表名 KNg8HYFW\
select name from sysobjects where type='U' *Ph]F$ZP
21、说明:列出表里的所有的 c 9rVgLqn!
select name from syscolumns where id=object_id('TableName') ?ork^4 $s
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。 24|
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 3p=vz'
显示结果: - $U@By<SJ
type vender pcs g b -Bxf
电脑 A 1 q0&Wk"X%rr
电脑 A 1 JE0?@PI$
光盘 B 2 xXF2"+
光盘 A 2 cV-i*L4X
手机 B 3 hwiKOP
手机 C 3 $[,l-[-+
23、说明:初始化表table1 U.: sK*
TRUNCATE TABLE table1 (nLKQV 1
24、说明:选择从10到15的记录 y-'" >
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc )8;{nqoC
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三、技巧 n!a<:]b<
1、1=1,1=2的使用,在SQL语句组合时用的较多 UxyY<H~Wx
"where 1=1" 是表示选择全部 "where 1=2"全部不选, *ksb?|<Ot
如: Z|
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if @strWhere !='' Y)|~:& tZ
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere dLZjB(0eO
end "3SWO3-x
else | H8^
begin wxj>W[V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' tw=K&/@^O
end 4.8nY\_WF
我们可以直接写成 }qAVN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere SET-8f
2、收缩数据库 %nWe,_PjD
--重建索引 GMb(10T`
DBCC REINDEX \^&
DBCC INDEXDEFRAG 34ha26\np
--收缩数据和日志 B oqJ
DBCC SHRINKDB #zt*xS[{0
DBCC SHRINKFILE P/MM
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3、压缩数据库 rnO0-h-;
dbcc shrinkdatabase(dbname) >Q=Ukn;k
4、转移数据库给新用户以已存在用户权限 zI^Da!r.
exec sp_change_users_login 'update_one','newname','oldname' M;KA]fmc
go ]9*;;4Mg
5、检查备份集 (bv,02
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' \0ov[T N.>
6、修复数据库 i.y=8GxY
ALTER DATABASE [dvbbs] SET SINGLE_USER mibpG9+d
GO o>F*Itr{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK +{$QAjW(/
GO 44HiTWQS?l
ALTER DATABASE [dvbbs] SET MULTI_USER C#;@y|Rw
GO ,gMy@
7、日志清除 #r<?v
SET NOCOUNT ON f8'MP9Lv
DECLARE @LogicalFileName sysname, D. Kqc
@MaxMinutes INT, lZWK2
@NewSize INT x6;j<m5Mjx
USE tablename -- 要操作的数据库名 Dx-KMiQ,"(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ufrqsv]=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. jQ=~g-y
@NewSize = 1 -- 你想设定的日志文件的大小(M) [A9JshMo
-- Setup / initialize _<zfQZai
DECLARE @OriginalSize int 0q,pi qjO
SELECT @OriginalSize = size R-rCh.
FROM sysfiles s+Q;pRZW{
WHERE name = @LogicalFileName )R?;M
SELECT 'Original Size of ' + db_name() + ' LOG is ' + g5S?nHS}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + c|AtBgvf
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' r-IT(DzkD
FROM sysfiles #yW\5)
WHERE name = @LogicalFileName Tycq1i^
CREATE TABLE DummyTrans .Cz %:%9
(DummyColumn char (8000) not null) ;o-yQmdh
DECLARE @Counter INT,
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@StartTime DATETIME, XK
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@TruncLog VARCHAR(255) @Uo6>-WF
SELECT @StartTime = GETDATE(), 3yA2WW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7&B$HZ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^ qvZ XS
EXEC (@TruncLog) L}sx<=8.m
-- Wrap the log if necessary. T
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +jP~s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) P"_$uO( 5x
AND (@OriginalSize * 8 /1024) > @NewSize #VVr"*7$
BEGIN -- Outer loop. 3c3OG.H$8
SELECT @Counter = 0 |=dC
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) [10zTU`
BEGIN -- update :5fAPK2r<
INSERT DummyTrans VALUES ('Fill Log') ^tH#YlV4>9
DELETE DummyTrans Te,$M3|
SELECT @Counter = @Counter + 1 n_nl{
END >[10H8~bI/
EXEC (@TruncLog) M@Q3M(z
END gI]GUD-
SELECT 'Final Size of ' + db_name() + ' LOG is ' + w
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + od' /%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' h"+ `13
FROM sysfiles SHVWwoieT
WHERE name = @LogicalFileName mLk(y*
DROP TABLE DummyTrans &>g'$a<[
SET NOCOUNT OFF .;7> y7$*
8、说明:更改某个表 ^P'{U26
exec sp_changeobjectowner 'tablename','dbo' "=/ f$Xf
9、存储更改全部表 U_G gCI)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^' M>r(t
@OldOwner as NVARCHAR(128), SQ*k =4*r
@NewOwner as NVARCHAR(128) Z;l`YK^-
AS b</9Ai=
DECLARE @Name as NVARCHAR(128) =ONHKF[UJ
DECLARE @Owner as NVARCHAR(128) +HT1 ct+dI
DECLARE @OwnerName as NVARCHAR(128) ) 0 W`
DECLARE curObject CURSOR FOR [BBEEI=|r
select 'Name' = name, u+H;
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'Owner' = user_name(uid) -s|8<A||"
from sysobjects C'yppl%
where user_name(uid)=@OldOwner |*/[`|*G
order by name XQ%4L-rhN
OPEN curObject =Z=o#46JY
FETCH NEXT FROM curObject INTO @Name, @Owner uDw.|B2ui
WHILE(@@FETCH_STATUS=0) c9qR'2
BEGIN Y6i _!z[V[
if @Owner=@OldOwner 7\]E~/g
begin Q\ /uKQ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) k3?rp`V1
exec sp_changeobjectowner @OwnerName, @NewOwner L( T12s
end hpTDxh'?$C
-- select @name,@NewOwner,@OldOwner D:^$4}h
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FETCH NEXT FROM curObject INTO @Name, @Owner -HSs^dP`
END AfeCK1mC @
close curObject i%e7LJ@5AW
deallocate curObject _Z5Mw+=19
GO FR2=
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10、SQL SERVER中直接循环写入数据 ,p(<+6QZ
declare @i int 2(5ebe[
set @i=1 ['8!qr
while @i<30 <)+y=m\eJ
begin !EUan
insert into test (userid) values(@i) gs!(;N\j|
set @i=@i+1 pym!U@$t
end bR@p<;G|
小记存储过程中经常用到的本周,本月,本年函数 4_Dp+^JF
Dateadd(wk,datediff(wk,0,getdate()),-1) R.=}@oPb
Dateadd(wk,datediff(wk,0,getdate()),6) iq(
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Dateadd(mm,datediff(mm,0,getdate()),0) __mF?m
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |rm g#;/D
Dateadd(yy,datediff(yy,0,getdate()),0) UAoh`6vFF8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ca+5=+X7
上面的SQL代码只是一个时间段 Ft}@1w5
Dateadd(wk,datediff(wk,0,getdate()),-1) Zd"^</ S
Dateadd(wk,datediff(wk,0,getdate()),6) Eke5Nb
就是表示本周时间段. 4apL4E"r
下面的SQL的条件部分,就是查询时间段在本周范围内的: }&_/PA0j
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Sa2>`":d
而在存储过程中 oudxm[/U
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $D G?M6
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) f^W;A"+