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'#QX
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一、基础 f3El9[
1、说明:创建数据库 Vb yGr~t
CREATE DATABASE database-name 4
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2、说明:删除数据库 AqnDsr!
drop database dbname )WuU?Tn&
3、说明:备份sql server 6Lj=%&
--- 创建 备份数据的 device ,j E'd'$
USE master Fjch<gAofS
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' T;!: A
--- 开始 备份 }-4@EC>
BACKUP DATABASE pubs TO testBack zW.I7Z0^
4、说明:创建新表 Jmg<mjq/G
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Gmi ^2?Z(
根据已有的表创建新表: .,[NJ:l
A:create table tab_new like tab_old (使用旧表创建新表) B?n
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B:create table tab_new as select col1,col2... from tab_old definition only &.^(,pt
5、说明:删除新表 7~&
drop table tabname s2F<H#
6、说明:增加一个列 }.*"ezaZw
Alter table tabname add column col type Jy<hTd*q
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。 oHh~!#u
7、说明:添加主键: Alter table tabname add primary key(col) b* (~8JxZ
说明:删除主键: Alter table tabname drop primary key(col) nYy%=B|>
8、说明:创建索引:create [unique] index idxname on tabname(col....) f4[fXP;A
删除索引:drop index idxname M:TN^ rA|
注:索引是不可更改的,想更改必须删除重新建。 0>{&8:
9、说明:创建视图:create view viewname as select statement Ad7N'1O
删除视图:drop view viewname fz>3
10、说明:几个简单的基本的sql语句 VS`
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选择:select * from table1 where 范围 E&>3 {uZI
插入:insert into table1(field1,field2) values(value1,value2) ]6s7?07m4
删除:delete from table1 where 范围 8.JFQ/)i
更新:update table1 set field1=value1 where 范围 $[(amj-;l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7 6 nrDE
排序:select * from table1 order by field1,field2 [desc] \EI<1B
总数:select count as totalcount from table1 J34/rL/s
求和:select sum(field1) as sumvalue from table1 3QSA|
平均:select avg(field1) as avgvalue from table1 }OZut!_
最大:select max(field1) as maxvalue from table1 l/*NscYtQ
最小:select min(field1) as minvalue from table1 l$_q#Kd
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11、说明:几个高级查询运算词 ?OjZb'+=K
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A: UNION 运算符 y0}3s)lKv
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。 fhwJ
B: EXCEPT 运算符 )WWqi,T}
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。 k65V5lb
C: INTERSECT 运算符 _"0,
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。 7 +]+S`p
注:使用运算词的几个查询结果行必须是一致的。 ~t=73fwB
12、说明:使用外连接 iEx
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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。 v;6O# ta'
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 fl@=h[g#t
B:right outer join: x)}.@\&%
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。 )\aCeY8o
C:full outer join: ce56$L8[
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 W0-KFo.'
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二、提升 meF.`fh
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,]Gi942
法一:select * into b from a where 1<>1 yV.E+~y
法二:select top 0 * into b from a Th.Mn}1%L
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) RKi11z
insert into b(a, b, c) select d,e,f from b;
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) sOVbz2\yb
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \:mZ)f3K=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TKH!,Ow9A
4、说明:子查询(表名1:a 表名2:b) qX9x#92
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) L.ML0H-
5、说明:显示文章、提交人和最后回复时间 Nh^
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4
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6、说明:外连接查询(表名1:a 表名2:b) I@/s&$H`l
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =# /BCL7
7、说明:在线视图查询(表名1:a ) hnYL<<AA
select * from (SELECT a,b,c FROM a) T where t.a > 1; r'F)8%
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 /`kM0=MMa
select * from table1 where time between time1 and time2 {D{'
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select a,b,c, from table1 where a not between 数值1 and 数值2 18eB\4NlD
9、说明:in 的使用方法 D`9 a"o
select * from table1 where a [not] in ('值1','值2','值4','值6') (_0r'{`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 e'l@M$^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ZbAg^2
11、说明:四表联查问题: (/i?Fd
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ?+P D?c7
12、说明:日程安排提前五分钟提醒 PKjM1wqaG@
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 H@uDP
13、说明:一条sql 语句搞定数据库分页 -prc+G,qyp
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 %|izt/B
14、说明:前10条记录 DS|HN
select top 10 * form table1 where 范围 XG!s+ShFV
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) :aHLr[%Mz
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) TC* 78;r
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 >OxSrc@A
(select a from tableA ) except (select a from tableB) except (select a from tableC) ).$q9G
17、说明:随机取出10条数据 ,&F4|{
select top 10 * from tablename order by newid() EP'I
18、说明:随机选择记录 <$>Jsv
select newid() Bj`ZH~T
19、说明:删除重复记录 F1A7l"X]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) q)f-z\
20、说明:列出数据库里所有的表名 w7E7r?)Wl|
select name from sysobjects where type='U' k.n-JS
21、说明:列出表里的所有的 z)_h"y?H{%
select name from syscolumns where id=object_id('TableName') 6%A_PP3Z
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 X,mqQ7+
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 4:0y\M5u
显示结果: Vh}F#~BrI
type vender pcs H&*KpOL
电脑 A 1 qP5'&!s&!
电脑 A 1 BG9.h!
光盘 B 2 `JAM]qB"
光盘 A 2 X/qLg+X
手机 B 3 TgjM@ir
手机 C 3 y#iQ
23、说明:初始化表table1 uGz>AW8a3
TRUNCATE TABLE table1 dWi:V7t+
24、说明:选择从10到15的记录 [/Vi*Z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc oYmLJzCf
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三、技巧 |*5HNP
1、1=1,1=2的使用,在SQL语句组合时用的较多 efrVF5,y?
"where 1=1" 是表示选择全部 "where 1=2"全部不选, x T8pwTO
如: (x!Tb2mlk
if @strWhere !='' ;r3Xh)k;
begin <$@*'i^7Ez
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere U][\|8i
end oYR OGU
else [))TL
begin h%PbM`:}6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' RQO&F$R=
end :~wU/dEEiz
我们可以直接写成 P*:9u>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere `G_k~ %
2、收缩数据库 ;_6CV
--重建索引 u`
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DBCC REINDEX _j sJS<21
DBCC INDEXDEFRAG 6F:<c
--收缩数据和日志 x^V9;V@6
DBCC SHRINKDB Ftw;T|
DBCC SHRINKFILE
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3、压缩数据库 c]PG5f xf
dbcc shrinkdatabase(dbname) jnIf(a
4、转移数据库给新用户以已存在用户权限 %f1>cO9[
exec sp_change_users_login 'update_one','newname','oldname' .H#<yPty
go UAEu.AT
5、检查备份集 UlQS]f~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' tDQuimYu7
6、修复数据库 ]9PQKC2&
ALTER DATABASE [dvbbs] SET SINGLE_USER Me2qOc^Z-
GO sL!+&Id|
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ',bSJ4)Y
GO zPc kM)
ALTER DATABASE [dvbbs] SET MULTI_USER 2Fc>6]:*
GO SUN!8
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7、日志清除 k1E(SXcW9
SET NOCOUNT ON kK~,?l
DECLARE @LogicalFileName sysname, nm#,oX2C
@MaxMinutes INT, 60z8U#upM
@NewSize INT hCpcX"wND
USE tablename -- 要操作的数据库名 _ K Ix7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 T*{nf
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ZwOX ,D
@NewSize = 1 -- 你想设定的日志文件的大小(M) bnZ~jOHl
-- Setup / initialize bmQ-5SE
DECLARE @OriginalSize int ~-2Gx
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SELECT @OriginalSize = size 4GqwY"ja
FROM sysfiles ?:DUsg
WHERE name = @LogicalFileName d:8c}t2X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^_c6Op<F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #p7K2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ]$&N"&q
FROM sysfiles ]114\JE
WHERE name = @LogicalFileName k9m9IE"9=$
CREATE TABLE DummyTrans {$QkerW3
(DummyColumn char (8000) not null) &w%--!T
DECLARE @Counter INT, EECuJ+T
@StartTime DATETIME, ;Q>+#5H6F8
@TruncLog VARCHAR(255) Fk#$@^c@
SELECT @StartTime = GETDATE(), *ry}T=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0b(x@>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) mX5%6{],
EXEC (@TruncLog) `6xr:s
-- Wrap the log if necessary. G\(cnqHk
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^m['VK#?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) !2F X l;
AND (@OriginalSize * 8 /1024) > @NewSize e!=~f%c<N
BEGIN -- Outer loop. Om_-#S
SELECT @Counter = 0 mqK}yK^P]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) A)_HSIVi
BEGIN -- update Q<>b3X>O
INSERT DummyTrans VALUES ('Fill Log') Ajm4q_
DELETE DummyTrans \b*z<Odv
SELECT @Counter = @Counter + 1 u{Gci
END x|$|~6f=n
EXEC (@TruncLog) 0k G\9
END gC+?5_=<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + CUnBi? Mi
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <,*3Av
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' TPVB{
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FROM sysfiles >%H(0G#X
WHERE name = @LogicalFileName =2@V}
DROP TABLE DummyTrans JbAmud,
SET NOCOUNT OFF )&j@ ={0
8、说明:更改某个表 y96HTQ32
exec sp_changeobjectowner 'tablename','dbo' \Oxyc}&
9、存储更改全部表 d:pGdr& .
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch X?U'GLm
@OldOwner as NVARCHAR(128), yA#nnu1
@NewOwner as NVARCHAR(128) 8a3EVc
AS C6'K)P[p
DECLARE @Name as NVARCHAR(128) e}+Zj'5
DECLARE @Owner as NVARCHAR(128) K3k{q90
DECLARE @OwnerName as NVARCHAR(128) h [@}}6
DECLARE curObject CURSOR FOR MK(~
select 'Name' = name, s:3b. *t<
'Owner' = user_name(uid) :$*@S=8 O
from sysobjects NfWL3"&X
where user_name(uid)=@OldOwner
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order by name zGNmc7
OPEN curObject JwQ/A[b
FETCH NEXT FROM curObject INTO @Name, @Owner =~>g--^U
WHILE(@@FETCH_STATUS=0) 82iFk`)T
BEGIN sYbmL`{
if @Owner=@OldOwner p\R&vof*
begin !Df>Q5~g
set @OwnerName = @OldOwner + '.' + rtrim(@Name) .C` YO2,
exec sp_changeobjectowner @OwnerName, @NewOwner EbG&[v
end @H8DGeM
-- select @name,@NewOwner,@OldOwner (K_{a+$[
FETCH NEXT FROM curObject INTO @Name, @Owner 5z&>NI
END 6Ad C
close curObject >Ptu-*
deallocate curObject ]iMqIh"
GO [
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10、SQL SERVER中直接循环写入数据 pI_dV44W
declare @i int L{rd',
set @i=1 W{c
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while @i<30 GVhy
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begin k{H7+;_
insert into test (userid) values(@i) z'7XGO'Lo
set @i=@i+1 e/&^~ $h
end E\ls- (,
小记存储过程中经常用到的本周,本月,本年函数 3m| C8:
Dateadd(wk,datediff(wk,0,getdate()),-1) THARr#1b};
Dateadd(wk,datediff(wk,0,getdate()),6) O?O=]s
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Dateadd(mm,datediff(mm,0,getdate()),0) ?:h*=0>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) N=\weuED
Dateadd(yy,datediff(yy,0,getdate()),0) pD('6C;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) fW[ .Q0
上面的SQL代码只是一个时间段 wr5v-_7r,
Dateadd(wk,datediff(wk,0,getdate()),-1) FA+"t^q
Dateadd(wk,datediff(wk,0,getdate()),6) 7]9,J(:Ed
就是表示本周时间段. c8T| o=`k6
下面的SQL的条件部分,就是查询时间段在本周范围内的: }[R-)M
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &%%ix#iF
而在存储过程中 5YneoM]Q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "8"aYD_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9w~SzpJ%