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。 F:.rb
Ei
a %"My;8
GJ=<~S"
一、基础 !5Ko^: +Y
1、说明:创建数据库 W8Z&J18AU
CREATE DATABASE database-name 8[SiIuIV
2、说明:删除数据库 [kx_Izi/T
drop database dbname 2T &<jt
3、说明:备份sql server vu[+UF\G
--- 创建 备份数据的 device 4tTK5`7N
USE master +A 6xY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' T|NNd1>
--- 开始 备份 9FT;?~,
BACKUP DATABASE pubs TO testBack r5XG$:$8\
4、说明:创建新表 CwQgA%)!i
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) d]0.6T1[K
根据已有的表创建新表: )6#dxb9
A:create table tab_new like tab_old (使用旧表创建新表) e%w>QN`
B:create table tab_new as select col1,col2... from tab_old definition only ~ y%8uHL:
5、说明:删除新表 <N11$t&_
drop table tabname "q(#,,_
6、说明:增加一个列 klduJT
>
Alter table tabname add column col type C`c;I7
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。 $v?+X20
7、说明:添加主键: Alter table tabname add primary key(col) Z
55iq
说明:删除主键: Alter table tabname drop primary key(col) UXVjRY`M.\
8、说明:创建索引:create [unique] index idxname on tabname(col....) f}g )3+i
删除索引:drop index idxname tuuc9H4B
注:索引是不可更改的,想更改必须删除重新建。 V3fd]rIP
9、说明:创建视图:create view viewname as select statement !8^:19+
删除视图:drop view viewname je1f\N45
10、说明:几个简单的基本的sql语句 *R.Q!Lv+
选择:select * from table1 where 范围 TIbqUR
插入:insert into table1(field1,field2) values(value1,value2) jW5n^Y)
删除:delete from table1 where 范围 "$KU+?
更新:update table1 set field1=value1 where 范围 76a+|TzR
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! vr<6j/ty
排序:select * from table1 order by field1,field2 [desc] $}0q=Lg%wv
总数:select count as totalcount from table1 w?6"`Mo
求和:select sum(field1) as sumvalue from table1 FN5*pVD;<
平均:select avg(field1) as avgvalue from table1 O^v^GG=e;C
最大:select max(field1) as maxvalue from table1 `JyTS~v$
最小:select min(field1) as minvalue from table1 uM,bO*/f
S?Q4u!FC
S+>1yvr),
%-!ruc"}
11、说明:几个高级查询运算词 TSXa#SKp
:SilQm*Pl
Ml)~%ZbF
A: UNION 运算符 6k"'3AKaR
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。 keNPlK%>
B: EXCEPT 运算符 mHjds77e
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。 a<l(zJptG
C: INTERSECT 运算符 qt5CoxeJ
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。 O7|0t\)
注:使用运算词的几个查询结果行必须是一致的。 Kl<qp7o0
12、说明:使用外连接 [$)C(1zY
A、left outer join: [@Y<:6
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 deSrs:.
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c m`!C|?hu
B:right outer join: }I;A\K]
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `T2RaWR4=
C:full outer join: Mi&,64<
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 =s`\W7/;{-
/%Lj$]S7[4
6%Ap/zvCZ>
二、提升 ALS\}_8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <d~P;R(@
法一:select * into b from a where 1<>1 8MgoAX,p
法二:select top 0 * into b from a ~TCz1UWV
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) U2z1HIs
insert into b(a, b, c) select d,e,f from b; !0:uM)_k
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) rmmN2+H
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Y<M,/Y_ !
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. qy=4zOOD#
4、说明:子查询(表名1:a 表名2:b)
]5W0zNb*
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) WUx}+3eWv
5、说明:显示文章、提交人和最后回复时间 rH7|r\] r
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b vt}+d
StUm
6、说明:外连接查询(表名1:a 表名2:b) 8qL*Nf
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c UA$
XjP
7、说明:在线视图查询(表名1:a ) So?SBh1C
select * from (SELECT a,b,c FROM a) T where t.a > 1; |>a sGP
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 1lZl10M:f
select * from table1 where time between time1 and time2 N%!8 I
select a,b,c, from table1 where a not between 数值1 and 数值2 mh;<lW\K/Z
9、说明:in 的使用方法 ~;O|$xL
select * from table1 where a [not] in ('值1','值2','值4','值6') .VN "j
10、说明:两张关联表,删除主表中已经在副表中没有的信息 )K.~A&y@
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @.ebQR-:H
11、说明:四表联查问题: v'0A$`w`
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 ..... k"F5'Od
12、说明:日程安排提前五分钟提醒 b=v
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s 7re
13、说明:一条sql 语句搞定数据库分页 ^Ts|/+}'i
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 |r5 n p
14、说明:前10条记录 $A\fm`
select top 10 * form table1 where 范围 /,dcr*
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) x'_I{$C&
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
%[0V>
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 |SC^H56+
(select a from tableA ) except (select a from tableB) except (select a from tableC) /n;-f%dL
17、说明:随机取出10条数据 Lbk?( TL
select top 10 * from tablename order by newid() 3a #2 }
18、说明:随机选择记录 ^T`)ltI]V
select newid() Xwy0dXko
19、说明:删除重复记录 3/V&PDC*'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) .w3.zZ0[
20、说明:列出数据库里所有的表名 vcs=!Ace
select name from sysobjects where type='U' R{GOlxKs C
21、说明:列出表里的所有的 "mc/fp
select name from syscolumns where id=object_id('TableName') (&R/ns~
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。 @Z> {/
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 ]TQ2PVN2
显示结果: 4eTfb
type vender pcs : xI SS
电脑 A 1 }eh<F^
电脑 A 1 7K3S\oPej
光盘 B 2 '"&M4.J{
光盘 A 2 q eLfO
手机 B 3 }}y$T(:l
手机 C 3 X@KF}x's
23、说明:初始化表table1 p\OUx Am
TRUNCATE TABLE table1 h<2o5c|
24、说明:选择从10到15的记录 x`K<z
J
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?t++IEoP
8o43J;mA
eS(\E0%QI
h^R EBPe
三、技巧 JVbR5"+.
1、1=1,1=2的使用,在SQL语句组合时用的较多 s<VNW
"where 1=1" 是表示选择全部 "where 1=2"全部不选, zhtNL_
如: +-YMW;5
if @strWhere !='' 7/QQ&7+NkS
begin p>Dv&fX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere gSQq
end 6Mu_9UAl`
else *YmR7g |k
begin sFv68Ag+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qYFOHu
end 0dxEV]
我们可以直接写成 dPplZ,Y%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &}:'YK*X
2、收缩数据库 \'Oi0qo>
--重建索引 o))z8n?b
DBCC REINDEX m
"'
DBCC INDEXDEFRAG /H.w0fu&.S
--收缩数据和日志 L+,p#w
DBCC SHRINKDB %+gYZv-
DBCC SHRINKFILE g&eIfm
3、压缩数据库 i]&C=X
dbcc shrinkdatabase(dbname) `|?K4<5|
4、转移数据库给新用户以已存在用户权限 )90 Q
exec sp_change_users_login 'update_one','newname','oldname' 3)\jUVuj
go Qgx9JJ>
5、检查备份集 9IJBK
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' R6l`IlG`
6、修复数据库 A;ip
V :)
ALTER DATABASE [dvbbs] SET SINGLE_USER 6'CZfs\
GO 2F9Gx;}t5=
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~+w'b7T,=
GO D^qto{!
ALTER DATABASE [dvbbs] SET MULTI_USER Sy|fX_i
GO IcmTF #{D
7、日志清除 AyHhq8Y
SET NOCOUNT ON }jHS
DECLARE @LogicalFileName sysname, MH@=Qqx#=t
@MaxMinutes INT, KMC]<
@NewSize INT rTTde^^_
USE tablename -- 要操作的数据库名 iAD'MB
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
UhKC:<%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. xgoG>~F
@NewSize = 1 -- 你想设定的日志文件的大小(M) Qj;wklq
-- Setup / initialize iUDN m|e
DECLARE @OriginalSize int U-~cVk+LI
SELECT @OriginalSize = size N$>.V7H&
FROM sysfiles |R$V[
WHERE name = @LogicalFileName EB R,j_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]}7FTMGbY
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ipzv]c&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' N{oi }i6
FROM sysfiles x!5b"
"
WHERE name = @LogicalFileName ;
kPx@C
CREATE TABLE DummyTrans 8@;|x2=y
(DummyColumn char (8000) not null) k1Z"Qmz
DECLARE @Counter INT, f_A'.oq+
@StartTime DATETIME, +tO mKY
@TruncLog VARCHAR(255) j9Qd
45
SELECT @StartTime = GETDATE(), <12 ia"}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?VCdT`6=
DBCC SHRINKFILE (@LogicalFileName, @NewSize) zT$-%
EXEC (@TruncLog) 4lrF{S8
-- Wrap the log if necessary. |v,%!ps
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9N1Uv,OtB
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {A!1s;
AND (@OriginalSize * 8 /1024) > @NewSize h-r\1{Q1]
BEGIN -- Outer loop. r{NCI
SELECT @Counter = 0 "^M/iv(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $sF'Sr{)y
BEGIN -- update aumWU{j=
INSERT DummyTrans VALUES ('Fill Log') U\OfB'Dn
DELETE DummyTrans &Xh8j^p'
SELECT @Counter = @Counter + 1 bloe|o!
END j v9DQr
EXEC (@TruncLog) VF#2I%R*
END ivTx6-]
SELECT 'Final Size of ' + db_name() + ' LOG is ' + |,YyuCQcL[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6.#5Ra
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' B%y?+4;zA
FROM sysfiles I*h%e,yIO
WHERE name = @LogicalFileName : jgvg$fd
DROP TABLE DummyTrans n^}M*#
SET NOCOUNT OFF a'zXLlXgGd
8、说明:更改某个表 2rxZN\gyL
exec sp_changeobjectowner 'tablename','dbo' T''PzY!Qf
9、存储更改全部表 wXUP%i]i=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch O*qSc^ 9q
@OldOwner as NVARCHAR(128), dKk\"6 o
@NewOwner as NVARCHAR(128) *=G~26*!V
AS ~>2DA$Ec
DECLARE @Name as NVARCHAR(128) ?
2#tIND
DECLARE @Owner as NVARCHAR(128) GFA D
DECLARE @OwnerName as NVARCHAR(128) W^U6O&-K
DECLARE curObject CURSOR FOR
kdmmfw
select 'Name' = name, r.-U=ql
'Owner' = user_name(uid) UXs=7H".
from sysobjects Sr$&]R]^
where user_name(uid)=@OldOwner -@*[
order by name j%w}hGW%,
OPEN curObject 6?B'3~r
FETCH NEXT FROM curObject INTO @Name, @Owner Evjvaa^
WHILE(@@FETCH_STATUS=0) |[6jf!F
BEGIN M:[rH
if @Owner=@OldOwner &P2tzY'
begin }G{ 'Rb
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [Eq7!_3
exec sp_changeobjectowner @OwnerName, @NewOwner |A .U~P):
end K!AW8FnHkZ
-- select @name,@NewOwner,@OldOwner XSfl'Fll D
FETCH NEXT FROM curObject INTO @Name, @Owner U2hPsF4f
END #:q$sKQ_$
close curObject whH_<@!
deallocate curObject JXT%@w>I
GO tccw0
10、SQL SERVER中直接循环写入数据 ,=Q;@Z4 vJ
declare @i int V1yY>
set @i=1 yM_ta '^$
while @i<30 F+!w[}0
begin %R?B=W7;Q
insert into test (userid) values(@i) K[,d9j`^
set @i=@i+1 *s=jKV#
end G
51l_
小记存储过程中经常用到的本周,本月,本年函数 XIep3l*
Dateadd(wk,datediff(wk,0,getdate()),-1) Ca2He}r`
Dateadd(wk,datediff(wk,0,getdate()),6) -'!K("
Dateadd(mm,datediff(mm,0,getdate()),0) _%r +?I
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 62-,!N 1-
Dateadd(yy,datediff(yy,0,getdate()),0) zcqv0lM '
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) [
GcH4E9r
上面的SQL代码只是一个时间段 vk:k ~
Dateadd(wk,datediff(wk,0,getdate()),-1) YGdzA]3>
Dateadd(wk,datediff(wk,0,getdate()),6) ^-wdIu~p?
就是表示本周时间段. n0\k(@+k
下面的SQL的条件部分,就是查询时间段在本周范围内的: r%:Q(|v?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $Gy&
而在存储过程中 kzkrvC+u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Sa8KCWgWh
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U{`Q_Uw@$: