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。 @|h9jx|
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一、基础 fAkfNH6
1、说明:创建数据库 U=%(kOx
CREATE DATABASE database-name [PXq<ST
2、说明:删除数据库 #P!<u Lc%
drop database dbname Sg%s\p]N_#
3、说明:备份sql server h[Sd3Z*
--- 创建 备份数据的 device iWWtL
USE master ^EN
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L~/L<M s
--- 开始 备份 `]]5!U2
BACKUP DATABASE pubs TO testBack =84EX<B
4、说明:创建新表 7Wv.-LD6
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 0NSw^dO\
根据已有的表创建新表: *Mg@j;+5s
A:create table tab_new like tab_old (使用旧表创建新表) ).HA#!SE
B:create table tab_new as select col1,col2... from tab_old definition only He8]Eb
5、说明:删除新表 m*1
drop table tabname {a\! 1~
6、说明:增加一个列 ,ye[TQ\,M
Alter table tabname add column col type W3ms8=z
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。 s;Bh69
7、说明:添加主键: Alter table tabname add primary key(col) 6?lAbW
说明:删除主键: Alter table tabname drop primary key(col) -vm1xp$
8、说明:创建索引:create [unique] index idxname on tabname(col....) E"[p_ALdC
删除索引:drop index idxname wIAH,3!
注:索引是不可更改的,想更改必须删除重新建。 !m))Yp-"H
9、说明:创建视图:create view viewname as select statement Tei2[siA5
删除视图:drop view viewname q%M~gp1
10、说明:几个简单的基本的sql语句 ,_$J-F?
选择:select * from table1 where 范围 ]}Ys4(}
插入:insert into table1(field1,field2) values(value1,value2) WnGi;AGH=1
删除:delete from table1 where 范围 ~u!V_su]GY
更新:update table1 set field1=value1 where 范围 ?zP
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 22ySMtxn
排序:select * from table1 order by field1,field2 [desc] vaQsG6q[
总数:select count as totalcount from table1 dYOY8r/
求和:select sum(field1) as sumvalue from table1 k8J zey]X
平均:select avg(field1) as avgvalue from table1 jLn#%Ia}
最大:select max(field1) as maxvalue from table1 AMB{Fssz
最小:select min(field1) as minvalue from table1 sWse
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11、说明:几个高级查询运算词 7MZH'nO
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A: UNION 运算符 UsA fZg8
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 E ,ilJl\
B: EXCEPT 运算符 &'zc2
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 t%e<]2-8
C: INTERSECT 运算符 ]Hl{(v\HO
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 f
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注:使用运算词的几个查询结果行必须是一致的。 K@:omT
12、说明:使用外连接 IP{$lC
A、left outer join: >h:'Z*9
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。 ^uG^>Om*
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 ]Ue
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B:right outer join: IDf\!QGx
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。 xR$T/] /
C:full outer join: czT2f
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 o+8H:7,o'
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二、提升 PPFt p3C
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !#%>,X#+
法一:select * into b from a where 1<>1 }8YY8|]LI
法二:select top 0 * into b from a /~".GZ&29
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) H)S!%(x4
insert into b(a, b, c) select d,e,f from b; {A< 9 61
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) KkTE -$-
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..
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4、说明:子查询(表名1:a 表名2:b) nC[aEZ7
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) WC=d@d)M
5、说明:显示文章、提交人和最后回复时间 Vh;|qF 9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b F
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6、说明:外连接查询(表名1:a 表名2:b) }%PK %/ zI
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o_b3G
7、说明:在线视图查询(表名1:a ) rZ n@i
select * from (SELECT a,b,c FROM a) T where t.a > 1; F_-xp1|
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 8oI|Z=
select * from table1 where time between time1 and time2 /;}%E
select a,b,c, from table1 where a not between 数值1 and 数值2 J2
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9、说明:in 的使用方法 |qj"p
select * from table1 where a [not] in ('值1','值2','值4','值6') V'>P lb.A
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ig YYkt
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) SWhzcqp
11、说明:四表联查问题: ;ow)N <Z
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 ..... uD?G\"L
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12、说明:日程安排提前五分钟提醒 `9^+KK "
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <[
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13、说明:一条sql 语句搞定数据库分页 ZI1]B944ni
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 e-v|
14、说明:前10条记录 'ZI8nMY
select top 10 * form table1 where 范围 }wp/,\_
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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.) }ssja,;
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }6.@
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 Ua:@,};
(select a from tableA ) except (select a from tableB) except (select a from tableC) }.'rhR+
17、说明:随机取出10条数据 2ry@<88
select top 10 * from tablename order by newid() ^Lc\{,m
18、说明:随机选择记录 _[E+D0A
select newid() 1|w@f&W"
19、说明:删除重复记录 k]$oir
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) P%Vq#5
20、说明:列出数据库里所有的表名 =+mb@#="m
select name from sysobjects where type='U' uJH[C>
21、说明:列出表里的所有的 \X\f~CB
select name from syscolumns where id=object_id('TableName') yZ[g2*1L
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 N>*+Wg$Ne
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 U/kQw rM
显示结果: zdU46|!u
type vender pcs AIn/v`JeX
电脑 A 1 EZjtZMnj
电脑 A 1 h/{1(c}
光盘 B 2 >P@VD"U
光盘 A 2 JttDRNZAU
手机 B 3 [PUu9rz#
手机 C 3 lqMr@
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23、说明:初始化表table1 6i+,/vr
TRUNCATE TABLE table1 -3)jUzD
24、说明:选择从10到15的记录 o<3$|`S&
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc y2jw3R
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三、技巧 4P1}XYD-2
1、1=1,1=2的使用,在SQL语句组合时用的较多 KgkRs?'z
"where 1=1" 是表示选择全部 "where 1=2"全部不选, N2'aC}
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如: j:'g*IxM_
if @strWhere !='' YK6'/2!
begin [yk-<}#B
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere I_z(ft.
end TbNH{w|p
else MaHP):~
begin MomHSv Q\
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 7p Y :.iVO
end `ROHB@-
我们可以直接写成 6uo;4}0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KfBT'6t
2、收缩数据库 300w\9fn&
--重建索引 VSDua.
DBCC REINDEX 2 HQ3G~U
DBCC INDEXDEFRAG X)~wB7_0G
--收缩数据和日志 4RtAwB
DBCC SHRINKDB 7LrmI~P
DBCC SHRINKFILE /qIl)+M
3、压缩数据库 rq8 d}wj
dbcc shrinkdatabase(dbname) 7g"u)L&32
4、转移数据库给新用户以已存在用户权限 ^O+ (eA7E
exec sp_change_users_login 'update_one','newname','oldname' >god++,o
go _7;:*'>a4
5、检查备份集 \298SH(!7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ; iia?f1
6、修复数据库 /o m++DxV
ALTER DATABASE [dvbbs] SET SINGLE_USER RhHm[aN
GO U3V5Jor#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1F`jptVQ\G
GO Px=@Tw N,
ALTER DATABASE [dvbbs] SET MULTI_USER 6^'BTd
GO qJdlZW<
7、日志清除 )'U0n`=
SET NOCOUNT ON ZzupK^5Z
DECLARE @LogicalFileName sysname, ySmbX
@MaxMinutes INT, [A,^F0:h
@NewSize INT ]$lt
USE tablename -- 要操作的数据库名 LO{Axf%
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 PZusYeV8b
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *l+Dbm,u
@NewSize = 1 -- 你想设定的日志文件的大小(M) + tMf&BZ
-- Setup / initialize \$wkr
DECLARE @OriginalSize int s||" } l
SELECT @OriginalSize = size :NF4[c
FROM sysfiles qtZ?
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WHERE name = @LogicalFileName PT6]qS'1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 1Q>nS[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |sReHt2)d
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ;cI*"-I:F
FROM sysfiles Y!CUUWM
WHERE name = @LogicalFileName DHWz, M
CREATE TABLE DummyTrans Fa )QDBz)
(DummyColumn char (8000) not null) *$<W"@%^J
DECLARE @Counter INT, [^5;XD:%&l
@StartTime DATETIME, }LT&BNZj
@TruncLog VARCHAR(255) dg24h7|]
SELECT @StartTime = GETDATE(), >SK:b/i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (6S'wb
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
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EXEC (@TruncLog) Q-
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-- Wrap the log if necessary. s;Gd`-S>d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired k9;^|Cm
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Jo\P,-\(
AND (@OriginalSize * 8 /1024) > @NewSize h<Aq|*
BEGIN -- Outer loop. ai/|qYf
SELECT @Counter = 0 K] (*l"'U5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1g{Pe`G,
BEGIN -- update ;v:(
INSERT DummyTrans VALUES ('Fill Log') P"Al*{:J
DELETE DummyTrans ;KlYiu
SELECT @Counter = @Counter + 1 hWT
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END w*ans}P7
EXEC (@TruncLog) qcj {rG18
END -d\sKc
SELECT 'Final Size of ' + db_name() + ' LOG is ' + CBEf;Ig
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + pUXoSnIq:
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 2jFuF71
FROM sysfiles eluN~T:W
WHERE name = @LogicalFileName "=djo+y
DROP TABLE DummyTrans 5G f@n/M"
SET NOCOUNT OFF T+<.KvO-
8、说明:更改某个表 -!j6&
exec sp_changeobjectowner 'tablename','dbo' q<dG}aj
9、存储更改全部表 *5%vU|9b
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch nF,F#V8l
@OldOwner as NVARCHAR(128), $eYL|?P50h
@NewOwner as NVARCHAR(128) KC6Cg?y^
AS lvO6&sF1
DECLARE @Name as NVARCHAR(128) e7RgA1
DECLARE @Owner as NVARCHAR(128) K*>%,mP$i
DECLARE @OwnerName as NVARCHAR(128) K oJ=0jM#
DECLARE curObject CURSOR FOR ec&/a2M
select 'Name' = name, $a M5jH<
'Owner' = user_name(uid) f4"UI-8;n
from sysobjects ]4l2jY
where user_name(uid)=@OldOwner UTD_rQ
order by name ??,[-Oi
OPEN curObject }Kp!,
FETCH NEXT FROM curObject INTO @Name, @Owner 8:,($a/KF
WHILE(@@FETCH_STATUS=0) kFn/dQ4|
BEGIN m4mE7Wn.3
if @Owner=@OldOwner O[Vet/^)
begin s?w2^<P
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1xB}Ed*k
exec sp_changeobjectowner @OwnerName, @NewOwner [eX]x
end ]vvYPRV76
-- select @name,@NewOwner,@OldOwner ("9bV8:@B
FETCH NEXT FROM curObject INTO @Name, @Owner h_%q`y ,
END .^Sglo
close curObject heVkCM :
deallocate curObject "v8p<JfB`
GO y [8;mCh
10、SQL SERVER中直接循环写入数据 D'g,<-ahl
declare @i int NKu[6J?)
set @i=1 wjA
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while @i<30 yLnQ9BXB&
begin t6DSZ^Zq
insert into test (userid) values(@i) +>Wo:kp3
set @i=@i+1 K-0=#6?y4
end Xz_WFLq4
小记存储过程中经常用到的本周,本月,本年函数 eZ$7VWG#
Dateadd(wk,datediff(wk,0,getdate()),-1) &93{>caf+
Dateadd(wk,datediff(wk,0,getdate()),6) o,6t:?Z
Dateadd(mm,datediff(mm,0,getdate()),0) 0k]ApW
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?jmP]MM
Dateadd(yy,datediff(yy,0,getdate()),0) \^!;r 9z=A
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) J9Ao*IW~
上面的SQL代码只是一个时间段 1BSd9Ydj
Dateadd(wk,datediff(wk,0,getdate()),-1) B9maz"lJ
Dateadd(wk,datediff(wk,0,getdate()),6) XO+BZB`F
就是表示本周时间段. M/N8bIC! Q
下面的SQL的条件部分,就是查询时间段在本周范围内的: Q{l,4P
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) bA^uzE
而在存储过程中 _~<sb,W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) e"E8BU
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $.PRav