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。 &>SE9w/?o
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一、基础 udMq>s;
1、说明:创建数据库 ~p&sd)
CREATE DATABASE database-name uP.3(n[&
2、说明:删除数据库 e8Jd*AKjb
drop database dbname %y'#@%kO:S
3、说明:备份sql server WD<M
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--- 创建 备份数据的 device ET4YoH>
USE master S"*wP[d.9
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' zKo,B/Ke4
--- 开始 备份 5n<Efi]j
BACKUP DATABASE pubs TO testBack t+t&eg
4、说明:创建新表 HzV3O-Qz]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 7y!{lr=n
根据已有的表创建新表: WukD|BCC
A:create table tab_new like tab_old (使用旧表创建新表) gU:jx
B:create table tab_new as select col1,col2... from tab_old definition only YRFM1?*
5、说明:删除新表 Dcq^C LPY
drop table tabname 9#+X?|p+0
6、说明:增加一个列 sHNt>5p
Alter table tabname add column col type cOSUe_S0w[
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。 hq|/XBd||
7、说明:添加主键: Alter table tabname add primary key(col) ]'Bz%[C)
说明:删除主键: Alter table tabname drop primary key(col) !U@[lBW
8、说明:创建索引:create [unique] index idxname on tabname(col....) K=V)"v5o3
删除索引:drop index idxname )9s[-W,e
注:索引是不可更改的,想更改必须删除重新建。 GKX#-zsh79
9、说明:创建视图:create view viewname as select statement IIzdCa{l
删除视图:drop view viewname ]'{<O3:7
10、说明:几个简单的基本的sql语句 z ,vjY$t:/
选择:select * from table1 where 范围 +]G;_/[2
插入:insert into table1(field1,field2) values(value1,value2) @>?&Mw\c
删除:delete from table1 where 范围 :^K|u^_>P
更新:update table1 set field1=value1 where 范围 QM=X<?m/,=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! k7? (IU
排序:select * from table1 order by field1,field2 [desc]
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总数:select count as totalcount from table1 u?!p[y6
求和:select sum(field1) as sumvalue from table1 |X>:"?4t
平均:select avg(field1) as avgvalue from table1 5bk5EE`
最大:select max(field1) as maxvalue from table1 x@yF|8
最小:select min(field1) as minvalue from table1 =73wngw
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11、说明:几个高级查询运算词 rxO|k0x^C
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A: UNION 运算符 N
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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。 h<[ o;E
B: EXCEPT 运算符 a!;?!f-i
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。 ?g1%-F+
C: INTERSECT 运算符 I%|W
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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。 \\_Qv
注:使用运算词的几个查询结果行必须是一致的。 $%LjIeVA5
12、说明:使用外连接 X=lOwPvP
A、left outer join: J*.qiUAgW
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 mhL,:UE
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k@^)>J^
B:right outer join: LbnR=B!
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 {$b]K-B
C:full outer join: e(sQgtM6
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。 t ;(kSg.
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二、提升 1N2s[ \q$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) m8.sHw
法一:select * into b from a where 1<>1 99vm7"5 hQ
法二:select top 0 * into b from a 9M<{@<]dm
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d+$a5 [^9
insert into b(a, b, c) select d,e,f from b; bX8Bn0#a+
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) +`zM^'^$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ie4}F|#=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &{99Owqg
4、说明:子查询(表名1:a 表名2:b) 0GEK xV\F
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) jvA]EN6$;~
5、说明:显示文章、提交人和最后回复时间 HKV]Rn
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .7"
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6、说明:外连接查询(表名1:a 表名2:b) (h%!Kun
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 72.ZE%Ue
7、说明:在线视图查询(表名1:a ) Ygr1 S(=
select * from (SELECT a,b,c FROM a) T where t.a > 1; w[t!?(![>
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ):1NeJOFF
select * from table1 where time between time1 and time2 K_(o
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select a,b,c, from table1 where a not between 数值1 and 数值2 p3&w/K{L6w
9、说明:in 的使用方法 G}d@^9FkE
select * from table1 where a [not] in ('值1','值2','值4','值6') 1s .Ose
10、说明:两张关联表,删除主表中已经在副表中没有的信息 lIz"mk
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pno]Bld'z
11、说明:四表联查问题: jU/0a=h9
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... =JY9K0S~
12、说明:日程安排提前五分钟提醒 wj/OYnMw
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }sZme3*J[
13、说明:一条sql 语句搞定数据库分页 8sLp! O;f2
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 b+,u_$@B
14、说明:前10条记录 h5>JBLawQP
select top 10 * form table1 where 范围 7YrX3Hx8
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.) 46Vx)xX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Mz_*`lRN
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 |}t[-a
(select a from tableA ) except (select a from tableB) except (select a from tableC) /aP4'U8ov
17、说明:随机取出10条数据 N^H~VG&D(
select top 10 * from tablename order by newid() ewN!7
18、说明:随机选择记录 B[}#m'Lv
select newid() })%WL;~
19、说明:删除重复记录 a!vF;J-Zqa
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ^h1EE=E"
20、说明:列出数据库里所有的表名 w|7<y8#qC
select name from sysobjects where type='U' jw]~g+x#$
21、说明:列出表里的所有的 l*rli[No
select name from syscolumns where id=object_id('TableName') D=i)AZqMPp
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;Wm{~Zhb
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 Tapj7/0`
显示结果: 0P_qtS
type vender pcs ?VmEbl
电脑 A 1 ]X%T^3%G
电脑 A 1 '#L.w6<B
光盘 B 2 \L Gj]mb1
光盘 A 2 :_X9x{
手机 B 3 eTw sh]
手机 C 3 v47Y7s:uQ
23、说明:初始化表table1 hi^@969
TRUNCATE TABLE table1 ~RgO9p(dY
24、说明:选择从10到15的记录 Us P1bh4
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E|P
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 9)}Nx>K
"where 1=1" 是表示选择全部 "where 1=2"全部不选, vau0Jn%=ck
如: z)*7LI
if @strWhere !='' >VIb|YA
begin XR3=Y0YDf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R-5EztmLae
end XpFW(v
else ;n0VF77>O
begin lC):$W
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' wC{?@h
end MZ]#9/
我们可以直接写成 SkU'JM7<95
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere G;Jqby8d
2、收缩数据库 ^U OVXRn
--重建索引 tj7{[3~-[
DBCC REINDEX
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DBCC INDEXDEFRAG fsRRnD
--收缩数据和日志 M@%$9N)gd
DBCC SHRINKDB KElzYZl8
DBCC SHRINKFILE 99)m d
3、压缩数据库 3z5w}qN]M
dbcc shrinkdatabase(dbname) 9[31EiT
4、转移数据库给新用户以已存在用户权限 6_1v~#
exec sp_change_users_login 'update_one','newname','oldname' |:Q`9;
go +a7J;-|
5、检查备份集 rRgP/E#_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ksb.]P d.
6、修复数据库 bLSXQStB
ALTER DATABASE [dvbbs] SET SINGLE_USER N{rC#A3
GO 8Evon&G59
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4K{<R!2I
GO 1HPYW7jk@"
ALTER DATABASE [dvbbs] SET MULTI_USER 6'E3Q=}d
GO Teo&V
7、日志清除 (^,4{;YQ5
SET NOCOUNT ON u6tD5Y
DECLARE @LogicalFileName sysname, !5FZxmUup
@MaxMinutes INT, ;]/>n:[E
@NewSize INT "kHFt|%@
USE tablename -- 要操作的数据库名 zPWJ=T@N
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 %VZQX_
@MaxMinutes = 10, -- Limit on time allowed to wrap log. A 9\]y%!
@NewSize = 1 -- 你想设定的日志文件的大小(M) &"G4yM
-- Setup / initialize |1M+FBT$w
DECLARE @OriginalSize int vMT:j
SELECT @OriginalSize = size "'i" @CR
FROM sysfiles }fzv9$]$
WHERE name = @LogicalFileName (4ueO~jb$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + yhwwF
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + >d1gVBhk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' VEUdw(-?s
FROM sysfiles 4Og&w]
WHERE name = @LogicalFileName DSb/+8KT
CREATE TABLE DummyTrans 'Ll,HgU;
(DummyColumn char (8000) not null) 6h8fzqRzc
DECLARE @Counter INT, L&*/s&>b
@StartTime DATETIME, sA!,)'6
@TruncLog VARCHAR(255) [
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SELECT @StartTime = GETDATE(), kta`[%KmIZ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,AX7~;hpq
DBCC SHRINKFILE (@LogicalFileName, @NewSize) I" AgRa
EXEC (@TruncLog) 7NG^I6WP-
-- Wrap the log if necessary. 6@N?`6Bt
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired pyvZ[R9
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /1s|FI$-L
AND (@OriginalSize * 8 /1024) > @NewSize f/!^QL{
BEGIN -- Outer loop. &}N=a
SELECT @Counter = 0 @t W;(8-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) UM?{ba9
BEGIN -- update CY{`IZ
INSERT DummyTrans VALUES ('Fill Log') (+_i^SqK
DELETE DummyTrans !4gyrNS
SELECT @Counter = @Counter + 1 UBN^dbP*
END ~i3/Ec0\
EXEC (@TruncLog) 8`edskWrU
END " w0[l"3V
SELECT 'Final Size of ' + db_name() + ' LOG is ' + DH@})TN*O
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + RfM
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -&3WN!egq
FROM sysfiles H?ZlJ|/c
WHERE name = @LogicalFileName ` #!~+
DROP TABLE DummyTrans Ujw J}j
SET NOCOUNT OFF x^s2bb
8、说明:更改某个表 Cq-d,
exec sp_changeobjectowner 'tablename','dbo' -5v2E-
9、存储更改全部表 o'9K8q\1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch aN\psg
@OldOwner as NVARCHAR(128), yW3X<
@NewOwner as NVARCHAR(128) X[F<sxw
AS XI>|"*-l
DECLARE @Name as NVARCHAR(128) aq a%B
DECLARE @Owner as NVARCHAR(128) 2d%j6D
DECLARE @OwnerName as NVARCHAR(128) IIn0w2:i
DECLARE curObject CURSOR FOR 1O<Gg<<,e
select 'Name' = name, 5)%bnLxn
'Owner' = user_name(uid) GoVB1)
from sysobjects G'*_7HD
where user_name(uid)=@OldOwner zP[_ccW@
order by name _3G;-iNX;
OPEN curObject m%mA0r
FETCH NEXT FROM curObject INTO @Name, @Owner ?B&Z x-krd
WHILE(@@FETCH_STATUS=0) BC/oh+FW3
BEGIN % FN3/iM
if @Owner=@OldOwner t6zc$0-j"
begin B5-G.Z
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ?52{s"N0>
exec sp_changeobjectowner @OwnerName, @NewOwner 'eKvt5&@
end vkQ81PEt
-- select @name,@NewOwner,@OldOwner /hC[>t<
FETCH NEXT FROM curObject INTO @Name, @Owner jQrj3b.NC3
END ^\Bm5QkS
close curObject ]}K\&ho2
deallocate curObject BseK?`]U"
GO %]~XbO
10、SQL SERVER中直接循环写入数据 K2=`.
declare @i int vXdz?
set @i=1 I(i/|S&^
while @i<30 i{['18Q$F3
begin OK=lp4X
insert into test (userid) values(@i) 8XwZJ\5
set @i=@i+1 pP1|/f5n`
end X)-9u 8
小记存储过程中经常用到的本周,本月,本年函数 .I6:iB
Dateadd(wk,datediff(wk,0,getdate()),-1) }7`HJ>+m)H
Dateadd(wk,datediff(wk,0,getdate()),6) Nk~Xz
Dateadd(mm,datediff(mm,0,getdate()),0) $Vu%4kq
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]e*Zx;6oi
Dateadd(yy,datediff(yy,0,getdate()),0) t>W^^'=E
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) /zB;1%m-
上面的SQL代码只是一个时间段 H(eGqVAq,
Dateadd(wk,datediff(wk,0,getdate()),-1) M7$ h
Dateadd(wk,datediff(wk,0,getdate()),6) Mn<G9KR
就是表示本周时间段. y;0k |C
下面的SQL的条件部分,就是查询时间段在本周范围内的: 'Gn-8r+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) aWp9K+4R$/
而在存储过程中 4v@urW s
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) fxW,S
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 50 s)5G#