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。 EL2z&
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一、基础 0lcwc"_DZX
1、说明:创建数据库 LS#_K-
CREATE DATABASE database-name #L*MMC"
2、说明:删除数据库 ww%4MHPp8
drop database dbname QZO<'q`L
3、说明:备份sql server +:c}LCI9<
--- 创建 备份数据的 device yd45y}uS;F
USE master U}=H1f,
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' v] Xy^7?
--- 开始 备份 n4"xVDL
BACKUP DATABASE pubs TO testBack 3z#fFP@E
4、说明:创建新表 eSMno_Gt3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^;\6ju2
根据已有的表创建新表: .>y3`,0h
A:create table tab_new like tab_old (使用旧表创建新表) +_f813$C
B:create table tab_new as select col1,col2... from tab_old definition only *_Pkb.3R
5、说明:删除新表 jlUT9Zp
drop table tabname s <$*A;t
6、说明:增加一个列 qe0ZM-C_
Alter table tabname add column col type `@:k*d
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。 Av/y
7、说明:添加主键: Alter table tabname add primary key(col) ?4Zo0DiUB
说明:删除主键: Alter table tabname drop primary key(col) #X5Tt ;
8、说明:创建索引:create [unique] index idxname on tabname(col....) N$ 2Iz
删除索引:drop index idxname vDc&m
注:索引是不可更改的,想更改必须删除重新建。 [{ A5BE -
9、说明:创建视图:create view viewname as select statement IY2f$YV
删除视图:drop view viewname 5hAs/i9_
10、说明:几个简单的基本的sql语句 tf9a- s
选择:select * from table1 where 范围 9w\C
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插入:insert into table1(field1,field2) values(value1,value2) 5y~B/.YY
删除:delete from table1 where 范围 #so"p<7 R
更新:update table1 set field1=value1 where 范围 %.{xo.`a[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |l?*' =
排序:select * from table1 order by field1,field2 [desc] gvP.\,U
总数:select count as totalcount from table1 mT1Q7ta*P
求和:select sum(field1) as sumvalue from table1 AIA4c"w.EO
平均:select avg(field1) as avgvalue from table1 '1\UFz
最大:select max(field1) as maxvalue from table1 f{]W*!VV-
最小:select min(field1) as minvalue from table1 GMob&0l8_
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11、说明:几个高级查询运算词 oYeFOw`
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A: UNION 运算符 >LEp EMJ\
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。 S?~/
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B: EXCEPT 运算符 7{f{SIB
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。 (*!4O>]
C: INTERSECT 运算符 qKuHd~M{ 1
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。 $I\lJ8
注:使用运算词的几个查询结果行必须是一致的。 <>=abgg
12、说明:使用外连接 twPD'X!r
A、left outer join: TiI3<.a!
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。 .ldBl
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 @#5?tk0
B:right outer join: (G{2ec:?
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。 ~$4!C'0
C:full outer join: v%Su#xq/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 NbhQ-
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二、提升 ^c>ROpic
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) AiV1
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法一:select * into b from a where 1<>1 X,+N/nku
法二:select top 0 * into b from a Otm7j>w
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "I[uD)$
insert into b(a, b, c) select d,e,f from b; {_J1m&/
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) NUX2{8gs
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [\ppK C
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ew8Manx
4、说明:子查询(表名1:a 表名2:b) LBhDP5qF
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) HwZ@T &_4
5、说明:显示文章、提交人和最后回复时间 N*>&XJ#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b IeE6?!,)
6、说明:外连接查询(表名1:a 表名2:b) 5'3H$%dC
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c T4"*w
7、说明:在线视图查询(表名1:a ) x*F_XE1#M
select * from (SELECT a,b,c FROM a) T where t.a > 1; jX91=78d
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 1Q??R}
select * from table1 where time between time1 and time2 +0n,>eDjg^
select a,b,c, from table1 where a not between 数值1 and 数值2 d7L|yeb"
9、说明:in 的使用方法 C;rK16cn
select * from table1 where a [not] in ('值1','值2','值4','值6') xo(3<1mD
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >zcp(M98
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,6^V)F
11、说明:四表联查问题: e&XJK*Wf
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ~2U5Wt
12、说明:日程安排提前五分钟提醒 )%(H'omvl
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 TZ@S?r>^
13、说明:一条sql 语句搞定数据库分页 Tn\59 (
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 TZS:(MJ9M
14、说明:前10条记录 (
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select top 10 * form table1 where 范围 P;lDri
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 17;qJ_T)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 4ew#@
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 v@]\
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(select a from tableA ) except (select a from tableB) except (select a from tableC) :.NCS`z_
17、说明:随机取出10条数据 w<=-n;2
select top 10 * from tablename order by newid() se]QEd7]7
18、说明:随机选择记录 ln=:E$jX
select newid() YU%U
19、说明:删除重复记录 L)/^%/!
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ]Saw}agE[%
20、说明:列出数据库里所有的表名 [%BWCd8Q~P
select name from sysobjects where type='U' P}bw Ej
21、说明:列出表里的所有的 tp=/f
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select name from syscolumns where id=object_id('TableName') WEB enGQ
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。 u69s}yZ
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 *Mr'/qp,
显示结果: 5JRj'G0I
type vender pcs l(
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电脑 A 1 G[[<-[C]5
电脑 A 1 -#"7F:N1
光盘 B 2 {,CvWL
光盘 A 2 Sc3 B*.
手机 B 3 W2j@Q=YDS
手机 C 3 GF awmNZ
23、说明:初始化表table1 a'A'%+2
TRUNCATE TABLE table1 $ &fm^1
24、说明:选择从10到15的记录 dRnO5
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc T6p2=o&p
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三、技巧 [^E{Yz=8,
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]h_V5rdX@
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ]u@`XVEJ
如: pj9s=}1 '
if @strWhere !='' [i)G:8U
begin 9jTm g%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5!^DKyw:
end *f( e`3E
else }=JuC+#~n
begin 05Go*QvV
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?513A>U
end Cu+u'&U!
我们可以直接写成 M-+=t8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere nfzKUJY
2、收缩数据库 DANndXQLH
--重建索引 07tSXl5!
DBCC REINDEX b_j8g{/9
DBCC INDEXDEFRAG 23=SXA!
--收缩数据和日志 ZpQ8KY$5
DBCC SHRINKDB ?e+$?8l[3
DBCC SHRINKFILE n"c3C)
3、压缩数据库 #mcU);s
dbcc shrinkdatabase(dbname) Kf-rthO
4、转移数据库给新用户以已存在用户权限 AT]Ty
exec sp_change_users_login 'update_one','newname','oldname' TdH~sz
go 9J'3b <
5、检查备份集 h9L/.>CX
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T hLR<\
6、修复数据库 !`F^LXGA
ALTER DATABASE [dvbbs] SET SINGLE_USER f$^+;j
GO [?Ub =sp
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK i@XFnt
GO CHRO9
ALTER DATABASE [dvbbs] SET MULTI_USER KdB9Q ;
GO (N25.}8Y
7、日志清除 '=eE6=m^K
SET NOCOUNT ON bkfk9P
DECLARE @LogicalFileName sysname,
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@MaxMinutes INT, vswBK-w(Z
@NewSize INT @n:.D9
USE tablename -- 要操作的数据库名 D&r2k
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 J=qPc}+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. H0 .,h;
@NewSize = 1 -- 你想设定的日志文件的大小(M) }8cX0mZ1j
-- Setup / initialize $1$T2'C~+
DECLARE @OriginalSize int <"XDIvpc%L
SELECT @OriginalSize = size F"M$ "rC]
FROM sysfiles %/x%hs;d
WHERE name = @LogicalFileName FI$#x%A
SELECT 'Original Size of ' + db_name() + ' LOG is ' + jB-)/8.qk
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N$SJK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +B0G[k7
FROM sysfiles ^ M4-O~
WHERE name = @LogicalFileName K'zG[[P
CREATE TABLE DummyTrans kwd)5J
(DummyColumn char (8000) not null) h*GU7<F:a
DECLARE @Counter INT, kGX;x}q
@StartTime DATETIME, 8fwM)DKS
@TruncLog VARCHAR(255) Ew kZzVuX
SELECT @StartTime = GETDATE(), t846:Z%[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' a:3f>0_t
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;c_pa0L
EXEC (@TruncLog) w+0Ch1$
-- Wrap the log if necessary. /o_h'l|PS
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired b|HH9\
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [d_sd
AND (@OriginalSize * 8 /1024) > @NewSize zsx12b^w
BEGIN -- Outer loop. )tV^)n[w
SELECT @Counter = 0 Z|kMoB
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) SLze) ?.
BEGIN -- update ?) ~j>1"S
INSERT DummyTrans VALUES ('Fill Log') $ (gR^L
DELETE DummyTrans q;V1fogqI)
SELECT @Counter = @Counter + 1 $iblLZhj
END t[ZumQ@HC
EXEC (@TruncLog) !F|iL
END !B3lsXLSY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hoQ?8}r:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + c.\J_^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' fii\&p7z
FROM sysfiles
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WHERE name = @LogicalFileName *I}_B\kY
DROP TABLE DummyTrans D@ji1$K
SET NOCOUNT OFF iY2%_b!5
8、说明:更改某个表 Q4;br?2H
exec sp_changeobjectowner 'tablename','dbo' j;k(AM<
9、存储更改全部表 0+\~^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %TJF+;
@OldOwner as NVARCHAR(128), YTco;5/
@NewOwner as NVARCHAR(128) ^<e"OV
AS o\luE{H
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DECLARE @Name as NVARCHAR(128) (qP !x 2j
DECLARE @Owner as NVARCHAR(128) 0P_Y6w+
DECLARE @OwnerName as NVARCHAR(128) QJG]z'c+
DECLARE curObject CURSOR FOR 63$ R')
select 'Name' = name, 2ju1<t,8)
'Owner' = user_name(uid) }fo?K|Xx
from sysobjects 79^on8 k}
where user_name(uid)=@OldOwner swDSV1alMB
order by name %V$ujun`
OPEN curObject N!fp;jvG
FETCH NEXT FROM curObject INTO @Name, @Owner TLL.Ch|#Y
WHILE(@@FETCH_STATUS=0) IP1|$b}sq
BEGIN C3 %, pDh
if @Owner=@OldOwner Te{L@sj
begin ^j2:fJOU#
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $Q:5KNF+p
exec sp_changeobjectowner @OwnerName, @NewOwner 7<=7RPWmD
end i#jCf3%+
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-- select @name,@NewOwner,@OldOwner "*@iXJxv5
FETCH NEXT FROM curObject INTO @Name, @Owner y(RbW_
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END g"3h#SMb
close curObject NRKAEf_#w
deallocate curObject uREc9z`Q'
GO ~P5!VNJ;r
10、SQL SERVER中直接循环写入数据 Ej1 [ry
declare @i int Dz&4za+{
set @i=1 b)u9#%Q
while @i<30 d]e`t"Aj
begin r)mm8MI!Z
insert into test (userid) values(@i) )N-+,Ms
set @i=@i+1 UY**3MK
end @ %z5]w
小记存储过程中经常用到的本周,本月,本年函数 l1odkNf|
Dateadd(wk,datediff(wk,0,getdate()),-1) n20H{TA
Dateadd(wk,datediff(wk,0,getdate()),6) IBVP4&}x$
Dateadd(mm,datediff(mm,0,getdate()),0) -}UCdaQ3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0zpP$q$
Dateadd(yy,datediff(yy,0,getdate()),0) P|.KMtG
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2597#O
上面的SQL代码只是一个时间段 nm'm*sU\
Dateadd(wk,datediff(wk,0,getdate()),-1) @D"1}CW
Dateadd(wk,datediff(wk,0,getdate()),6) S$"A[
就是表示本周时间段. |y%pP/;&!
下面的SQL的条件部分,就是查询时间段在本周范围内的: (6\A"jey\x
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?NI)3-l
而在存储过程中 %!rsu-W:Y
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Yb =8\<;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Pr<?E[