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。 1pl2;!
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一、基础 Y#.6d
1、说明:创建数据库 la1D2 lM
CREATE DATABASE database-name Ty(yh(oYF`
2、说明:删除数据库 {m>~`
drop database dbname +KYxw^k}"7
3、说明:备份sql server `=PB2'
--- 创建 备份数据的 device }b<87#Nb9R
USE master vC s6#PR$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' wZ}n3R,
--- 开始 备份 [k}dES#
BACKUP DATABASE pubs TO testBack `8qT['`#R
4、说明:创建新表 4/ 0/#G#j
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _-YL!oP
根据已有的表创建新表: S]Sp Z8
A:create table tab_new like tab_old (使用旧表创建新表) o
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B:create table tab_new as select col1,col2... from tab_old definition only 3/yt*cr
5、说明:删除新表 {A!;W
drop table tabname V_7Y1GD
6、说明:增加一个列 ~k"eEV
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Alter table tabname add column col type #%9oQ6nO
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 uS)RhA)
7、说明:添加主键: Alter table tabname add primary key(col) ^M[-K`c }
说明:删除主键: Alter table tabname drop primary key(col) MLEIx()
8、说明:创建索引:create [unique] index idxname on tabname(col....) h0&>GY;i
删除索引:drop index idxname 9
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注:索引是不可更改的,想更改必须删除重新建。 r|u6O F>
9、说明:创建视图:create view viewname as select statement OcyiL)tv 5
删除视图:drop view viewname qBf wN 1
10、说明:几个简单的基本的sql语句 5&GQ=m
选择:select * from table1 where 范围 Ew)n~!s
插入:insert into table1(field1,field2) values(value1,value2) 'Y~8_+J?
删除:delete from table1 where 范围 HMl!?%%
更新:update table1 set field1=value1 where 范围 OtrXYiKB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Wo<PmSt9i
排序:select * from table1 order by field1,field2 [desc] S&;T_^|
总数:select count as totalcount from table1 $cp16
求和:select sum(field1) as sumvalue from table1 'b?#4rq}
平均:select avg(field1) as avgvalue from table1 G!>
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最大:select max(field1) as maxvalue from table1 JI{OGr
最小:select min(field1) as minvalue from table1 )VV4HoH]8
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11、说明:几个高级查询运算词 E.WNykF-
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A: UNION 运算符 Q0[CH~
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 8\W3FvQ
B: EXCEPT 运算符 6KZ8 .m}:
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 rTm>8et
C: INTERSECT 运算符 3.GdKP.%
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Q
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注:使用运算词的几个查询结果行必须是一致的。 [E..VesrM
12、说明:使用外连接 g9grfN
A、left outer join:
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 a3(7{,Ew
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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B:right outer join: K"t:B
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 KNUMz4
C:full outer join: /o}0oo5B
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 s$+: F$Y0
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二、提升 jmA{rD W
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) \V!X& a
法一:select * into b from a where 1<>1 L`VQ{|&3V
法二:select top 0 * into b from a )ZuQ;p
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) sWpRX2{5,
insert into b(a, b, c) select d,e,f from b; }fa%JN %E
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) 6LF^[b/u
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 eA~_)-Z-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. x:&L?eOT
4、说明:子查询(表名1:a 表名2:b) c+G :@%
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) l#5k8+s
5、说明:显示文章、提交人和最后回复时间 t"Vr;0!{
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [>aoDJ
6、说明:外连接查询(表名1:a 表名2:b) <EM LiiNY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C\hZ;Z1
7、说明:在线视图查询(表名1:a ) .AmM%I4K
select * from (SELECT a,b,c FROM a) T where t.a > 1; zLIa! -C
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 *M\i4FO8
select * from table1 where time between time1 and time2 v2uS6
select a,b,c, from table1 where a not between 数值1 and 数值2 =[tls^
9、说明:in 的使用方法 |Bf:pG!
select * from table1 where a [not] in ('值1','值2','值4','值6') lLwQridFXh
10、说明:两张关联表,删除主表中已经在副表中没有的信息 VlQwVe
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) aR(Z~z;C
11、说明:四表联查问题: (HX [bG`
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 ..... bZ@53
12、说明:日程安排提前五分钟提醒 "'p+qbT8
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $d"f/bRWy
13、说明:一条sql 语句搞定数据库分页 j/` qd(=B
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 i6\!7D]
14、说明:前10条记录 NcY0pAR*
select top 10 * form table1 where 范围 W;AWO0+
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) i!+3uHWu`)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) R.WsC bU
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Qd)cFL"v
(select a from tableA ) except (select a from tableB) except (select a from tableC) HBf8!\0|/
17、说明:随机取出10条数据 `] dx%
select top 10 * from tablename order by newid() :$Di.|l@7
18、说明:随机选择记录 a.*j8T
select newid() -~GJ; Uw
19、说明:删除重复记录 )k%drdY{J'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) JU,ROoz(
20、说明:列出数据库里所有的表名 CCvBE, ux
select name from sysobjects where type='U' ';T5[l,
21、说明:列出表里的所有的 {*r$m>HpM
select name from syscolumns where id=object_id('TableName') GbrPtu2{@V
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 lp%.n= '\
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type \fFy$
显示结果: t=\[J+
type vender pcs bqwW9D(
电脑 A 1 1^"aR#
电脑 A 1 X\)KVn`
光盘 B 2 L-:L=
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光盘 A 2 /Rcd}rO
手机 B 3 i}{Q\#=#
手机 C 3 ]?^xc[
23、说明:初始化表table1 =4\~M"[p
TRUNCATE TABLE table1 nX aX=
24、说明:选择从10到15的记录 d"`>&8*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc v.&*z48
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三、技巧 8PVs!?Nne
1、1=1,1=2的使用,在SQL语句组合时用的较多 Dj&bHC5%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |}y}o:(
如: W%ZU& YBc
if @strWhere !='' !*.
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begin '#
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `V2j[Fz
end Wk#-LkI
else gJ~*rWBK:
begin f]65iE?x
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' x9
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end .vF<3p|
我们可以直接写成 _llaH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere l0 :xQV`
2、收缩数据库 wyEgm:Vt
--重建索引 /1
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DBCC REINDEX YHtI%
DBCC INDEXDEFRAG zk~ rKQ,
--收缩数据和日志 rX
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DBCC SHRINKDB 6]49kHgMhe
DBCC SHRINKFILE fB}5,22
3、压缩数据库 b<cM[GaV~
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 ,qqV11P]
exec sp_change_users_login 'update_one','newname','oldname' 9f[[%80
go 'MlC
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5、检查备份集 ^K[tO54
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' CrQ&-!Eh
6、修复数据库 ADUI@#vk
ALTER DATABASE [dvbbs] SET SINGLE_USER Nn\\}R
GO .]l2)OlLQ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n\DT0E]
GO `W S
ALTER DATABASE [dvbbs] SET MULTI_USER yKhzymS}T
GO ;$;/#8`>
7、日志清除 pD/S\E0@t
SET NOCOUNT ON /aEQ3x
DECLARE @LogicalFileName sysname, haK5Oe/cE
@MaxMinutes INT, tqC#_[~7
@NewSize INT W5g!`f
USE tablename -- 要操作的数据库名 d7gSkna`5c
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 m<ruFxY
@MaxMinutes = 10, -- Limit on time allowed to wrap log. &NnMz9
@NewSize = 1 -- 你想设定的日志文件的大小(M) !A0bbJ
-- Setup / initialize 8R D)yRJ
DECLARE @OriginalSize int 7!)%%K.z6
SELECT @OriginalSize = size s``L?9
FROM sysfiles |g+5rVbd
WHERE name = @LogicalFileName y>PbYjuIU
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bm?TMhC
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,' B=eY,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +y(h/NcQ
FROM sysfiles I{bi3y0
WHERE name = @LogicalFileName Rgu^>
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CREATE TABLE DummyTrans 5E=Odep`
(DummyColumn char (8000) not null) r2w7lf66!
DECLARE @Counter INT, >fQN"(tf
@StartTime DATETIME, + k:?;ZG
@TruncLog VARCHAR(255) AG2jl/
SELECT @StartTime = GETDATE(), h^,a 1'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' .ji%%f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) }hxYsI"d
EXEC (@TruncLog) "(GeW286k
-- Wrap the log if necessary. AR^Di`n!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired LPF?\mf ^4
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^u{$$.&
AND (@OriginalSize * 8 /1024) > @NewSize _aYQ(FO
BEGIN -- Outer loop. "Q4{6FH+mB
SELECT @Counter = 0 k=}hY+/=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I^=M>_s4
BEGIN -- update $la,_Sr
INSERT DummyTrans VALUES ('Fill Log') i9tM]/SP
DELETE DummyTrans C? S %fF
SELECT @Counter = @Counter + 1 f0+
END s]UeDZ<a
EXEC (@TruncLog) ?Fu.,srt
END C/G[B?:h
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $-73}[UA 4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {rQ`#?J}^?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F_`Gs8-VH
FROM sysfiles Dlp::U*N'
WHERE name = @LogicalFileName X,~C
DROP TABLE DummyTrans AsOI`@FV
SET NOCOUNT OFF A:(uK>5{Kk
8、说明:更改某个表 SbY i|V,H
exec sp_changeobjectowner 'tablename','dbo' R}FN6cH
9、存储更改全部表 ko$R%W&T
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch t*#T~3p
@OldOwner as NVARCHAR(128), c9V'Z d#
@NewOwner as NVARCHAR(128) XOMWqQr|
AS va\cE*,@ns
DECLARE @Name as NVARCHAR(128) ?FyA2q!
DECLARE @Owner as NVARCHAR(128) "\
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DECLARE @OwnerName as NVARCHAR(128) kmwFw>#
DECLARE curObject CURSOR FOR S3w? X
select 'Name' = name, } 2KuY\5\i
'Owner' = user_name(uid) p6p_B
from sysobjects L-yC 'C
where user_name(uid)=@OldOwner oVdmgmT.Y
order by name ZC"p^~U_e[
OPEN curObject DwPl,@T_i\
FETCH NEXT FROM curObject INTO @Name, @Owner x\WKsc
WHILE(@@FETCH_STATUS=0) (Q&Z/Fe
BEGIN S"*wP[d.9
if @Owner=@OldOwner S:wmm}XQ
begin _F3 :j9^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Y&nY]VV
exec sp_changeobjectowner @OwnerName, @NewOwner 8Pq|jK "
end *:iFhKFU
-- select @name,@NewOwner,@OldOwner $P$OWp?b
FETCH NEXT FROM curObject INTO @Name, @Owner sHNt>5p
END w5p+Yx=q
close curObject YC{od5a
deallocate curObject L]Uy+[gg
GO k2~j:&p
10、SQL SERVER中直接循环写入数据 CAk.2C/
declare @i int d4/ZOj+%
set @i=1 3LG)s:p$/
while @i<30 tlE+G@|^
begin (c;$^xZK
insert into test (userid) values(@i) -70Ut
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set @i=@i+1 xGjEEBL
end |X>:"?4t
小记存储过程中经常用到的本周,本月,本年函数 O:4.xe
Dateadd(wk,datediff(wk,0,getdate()),-1) E8/P D
Dateadd(wk,datediff(wk,0,getdate()),6) >354O6
Dateadd(mm,datediff(mm,0,getdate()),0) Y%2<}3P
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) C+_ NG
Dateadd(yy,datediff(yy,0,getdate()),0) _ 95V"h
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >Py=H+d!j
上面的SQL代码只是一个时间段 J^U#dYd
Dateadd(wk,datediff(wk,0,getdate()),-1) }2}hH0R
Dateadd(wk,datediff(wk,0,getdate()),6) X=lOwPvP
就是表示本周时间段. o}<}zTU
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6:Ra3!V"v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) {$b]K-B
而在存储过程中 p tMysYT'
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cJ&%XN
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ip~PF5