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。 1E=%:? d
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一、基础 M
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1、说明:创建数据库 K({+3vK
CREATE DATABASE database-name /`?i&\C3r
2、说明:删除数据库 `2Ju[P
drop database dbname w*u HB;?
3、说明:备份sql server 8L9xP'[^
--- 创建 备份数据的 device HBV~`0O$
USE master p4bQCI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &5)Kg%r
--- 开始 备份 srw5&s(3X
BACKUP DATABASE pubs TO testBack <dLdSEw
4、说明:创建新表 +\?#8U/k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) z2A7:[
根据已有的表创建新表: n!~{4
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A:create table tab_new like tab_old (使用旧表创建新表) vZq7U]RW
B:create table tab_new as select col1,col2... from tab_old definition only &d[&8V5S
5、说明:删除新表 u&9|9+"N
drop table tabname HhH[p E
6、说明:增加一个列 ;vc$;54K
Alter table tabname add column col type 4%aODr8
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ? D2:'gg
7、说明:添加主键: Alter table tabname add primary key(col) ]SFB_5Gb
说明:删除主键: Alter table tabname drop primary key(col) GGo
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8、说明:创建索引:create [unique] index idxname on tabname(col....) "=MRzSke3
删除索引:drop index idxname kG:uXbUI'
注:索引是不可更改的,想更改必须删除重新建。 =X2 Ieb
9、说明:创建视图:create view viewname as select statement (|Y[5O)
删除视图:drop view viewname [^A 93F
10、说明:几个简单的基本的sql语句 {ckA
选择:select * from table1 where 范围 mrS:||,_
插入:insert into table1(field1,field2) values(value1,value2) 6~ev5SD;f
删除:delete from table1 where 范围 6,ylkf3
更新:update table1 set field1=value1 where 范围 /Uz2.Ua=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S/"-x{Gc2v
排序:select * from table1 order by field1,field2 [desc] ,3qi]fFLMe
总数:select count as totalcount from table1 7ZI!$J|
求和:select sum(field1) as sumvalue from table1 .zAB)rNc
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平均:select avg(field1) as avgvalue from table1 EXK~Zf|&Z
最大:select max(field1) as maxvalue from table1 L ![b f5T
最小:select min(field1) as minvalue from table1 ;sT7c1X^!
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11、说明:几个高级查询运算词 ;Bd0 =C
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A: UNION 运算符 wv #1s3
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。 ]/XNfb
B: EXCEPT 运算符 ^D/:[
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。 MW &iNioX
C: INTERSECT 运算符 Q4JwX=ZVj
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。 5#p [Q _
注:使用运算词的几个查询结果行必须是一致的。 .36z
12、说明:使用外连接 rg]eSP3W
A、left outer join: r77?s?
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。 qhRs5QXL
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 =P!SN]nFeP
B:right outer join: wv|:-8V
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。 7[[XNJP
C:full outer join: EX7gTf#
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。 -\:pbR
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二、提升 v[T5D:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) RAxAy{
法一:select * into b from a where 1<>1 2_6x2Ia4
法二:select top 0 * into b from a a.L ?J
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4nzUDeI3MG
insert into b(a, b, c) select d,e,f from b; U{gJn#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) ]7}2"?J4v
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ]xBQ7Xqf|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^EdY:6NJ=A
4、说明:子查询(表名1:a 表名2:b) pP;GDW4
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) r in#lu&N
5、说明:显示文章、提交人和最后回复时间 &]iX>m.
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b /m%i"kki
6、说明:外连接查询(表名1:a 表名2:b) kep.+t[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~v$gk
7、说明:在线视图查询(表名1:a ) m/r4f279
select * from (SELECT a,b,c FROM a) T where t.a > 1; 8
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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 ^|5bK_Z&
select * from table1 where time between time1 and time2 )s4#)E1
select a,b,c, from table1 where a not between 数值1 and 数值2 ,kfUlv=
9、说明:in 的使用方法 ;]34l."85
select * from table1 where a [not] in ('值1','值2','值4','值6') m;)[gF
10、说明:两张关联表,删除主表中已经在副表中没有的信息 $/ew'h9q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) qP-*
11、说明:四表联查问题: ;?"2sS!AHQ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... K]yCt~A$
12、说明:日程安排提前五分钟提醒 J~9l+?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 yf(VwU,
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13、说明:一条sql 语句搞定数据库分页 ?ntyF-n&
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 yeqZPzn
14、说明:前10条记录 J'`,];su
select top 10 * form table1 where 范围 8q{
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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.) w+(bkqz]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) s"#>Xc
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 g|tnYN
(select a from tableA ) except (select a from tableB) except (select a from tableC) nKC$
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17、说明:随机取出10条数据 >_XRh
select top 10 * from tablename order by newid() YIGQDj@
18、说明:随机选择记录 Rb\M63q
select newid() h1} x2
19、说明:删除重复记录 2JwR?<n{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wyeiz7
20、说明:列出数据库里所有的表名 ; 6Js
select name from sysobjects where type='U' ~]a:9Ev*
21、说明:列出表里的所有的 73OFFKbsk
select name from syscolumns where id=object_id('TableName') 8Ih+^Y
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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。 3yn>9qt
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 N|Mzj|i.
显示结果: HWG5Ghu8,)
type vender pcs )<-\ F%&b
电脑 A 1 k;/U6,LQ*
电脑 A 1 /DA'p [,
光盘 B 2 6 6WAD$8$
光盘 A 2 L l\y2oJ
手机 B 3 U@yn%k9
手机 C 3 [GJ_]w^}j
23、说明:初始化表table1 :
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TRUNCATE TABLE table1 zBV7b| j
24、说明:选择从10到15的记录 A
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ORHs1/L`j
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三、技巧 Z;`ts/?SY]
1、1=1,1=2的使用,在SQL语句组合时用的较多 eD5.*O
"where 1=1" 是表示选择全部 "where 1=2"全部不选, *}DCxv
如: &[ejxK"
if @strWhere !='' 2'UWPZgE
begin Rqu_[M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere g0NtM%
end s ki'I
else J@ZIW%5
begin " )T;3/c
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' LK5,GWF;
end h BD .IB
我们可以直接写成 ]E$h7I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "u:5
2、收缩数据库 v#J2yg
--重建索引 ]JF>a_2wG
DBCC REINDEX O
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DBCC INDEXDEFRAG b:VCr ^vp
--收缩数据和日志 KfD=3h=
DBCC SHRINKDB {?yZdL:m)
DBCC SHRINKFILE |Am
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3、压缩数据库 T9N][5 \
dbcc shrinkdatabase(dbname) ] }XsP
4、转移数据库给新用户以已存在用户权限 y5gTd_-
exec sp_change_users_login 'update_one','newname','oldname' ^ur?da9z'
go <=2\xJfxB
5、检查备份集 ~Ry?}5&:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' FY1
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6、修复数据库 t[/WGF&(R
ALTER DATABASE [dvbbs] SET SINGLE_USER =?hGa;/rb
GO },<(VhP
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK %X)w$}WH
GO MHNuA,cz
ALTER DATABASE [dvbbs] SET MULTI_USER 91'i7&~xdG
GO KG7 ~)g
7、日志清除 %i[G6+-
SET NOCOUNT ON d^AXhQjQN-
DECLARE @LogicalFileName sysname, \>,[5|GU
@MaxMinutes INT, *9Eep~ 6
@NewSize INT
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USE tablename -- 要操作的数据库名 K@yLcgr{O2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _M[@a6?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. fg"]4&`j-
@NewSize = 1 -- 你想设定的日志文件的大小(M) +P YX.
-- Setup / initialize mcbvB5U
DECLARE @OriginalSize int W6STjtT3P
SELECT @OriginalSize = size ((OQs.
FROM sysfiles /o@6?UH
WHERE name = @LogicalFileName 2ZUI~:U Z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + xv|?;Zf6w
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + eQK}J]S<
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z',Z7QW7
FROM sysfiles W%Jw\ z=
WHERE name = @LogicalFileName &d}1)?
CREATE TABLE DummyTrans I_ O8 9Sgn
(DummyColumn char (8000) not null) $=&a0O#
DECLARE @Counter INT, &!Sq6<!v2
@StartTime DATETIME, c:? tn
@TruncLog VARCHAR(255) [{R^!Az&b<
SELECT @StartTime = GETDATE(), *nZe|)m
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Wgp}v93
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \piB*"ln
EXEC (@TruncLog) VS.~gHx
-- Wrap the log if necessary. Jkf%k3H3I*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired LdAWCBLS
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :@x_& b
AND (@OriginalSize * 8 /1024) > @NewSize LTsX{z
BEGIN -- Outer loop. ,v^A;,q
SELECT @Counter = 0 <V?csx/eRd
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) @-B)a Z
BEGIN -- update al#BfcZW
INSERT DummyTrans VALUES ('Fill Log') barY13)$U
DELETE DummyTrans U1oZ\Mh
SELECT @Counter = @Counter + 1 )I&,kH)+
END YCMXF#1
EXEC (@TruncLog) @q(sig00nr
END (*6kYkUK
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v*Dz4K#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + r>o#h+'AV
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ohLM9mc9
FROM sysfiles ,#/%Fn%T
WHERE name = @LogicalFileName ERka l7+
DROP TABLE DummyTrans LpV2XL$p>#
SET NOCOUNT OFF /J@<e{&t~
8、说明:更改某个表 Vv|%;5(
exec sp_changeobjectowner 'tablename','dbo' <I
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9、存储更改全部表 w;
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch &|]GTN`E
@OldOwner as NVARCHAR(128), m/E$0tf
@NewOwner as NVARCHAR(128) /-FvC^Fj
AS MP
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DECLARE @Name as NVARCHAR(128) ?**9hu\BG
DECLARE @Owner as NVARCHAR(128) :}B=Bk/q
DECLARE @OwnerName as NVARCHAR(128) +mu.W
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DECLARE curObject CURSOR FOR | XGj97#M
select 'Name' = name, S1vUP5cZ
'Owner' = user_name(uid) -e2f8PV?3
from sysobjects L<QjkFj
where user_name(uid)=@OldOwner e9\eh? bPU
order by name l.>3gjr
OPEN curObject A r=P;6J
FETCH NEXT FROM curObject INTO @Name, @Owner ZBY*C;[)*P
WHILE(@@FETCH_STATUS=0) dp|VQWCq
BEGIN jV
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if @Owner=@OldOwner :abpht
begin ;:WM^S
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &eA!h
exec sp_changeobjectowner @OwnerName, @NewOwner w%2|Po5
end .`ZuUr
-- select @name,@NewOwner,@OldOwner @A.7`*i_
FETCH NEXT FROM curObject INTO @Name, @Owner G~ONHXL
END GEs5@EH
close curObject ?S8_x]E
deallocate curObject 5$PDA*]9
GO 5+Ld1nom
10、SQL SERVER中直接循环写入数据 7QXp\<7
declare @i int >2^|r8l5
set @i=1 <V
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while @i<30 S%Bm4jY
begin ;t xW\iy%Z
insert into test (userid) values(@i) y$,j'B:;4m
set @i=@i+1 =".sCV9"N
end Dug{)h_2
小记存储过程中经常用到的本周,本月,本年函数 AqZ()p*z
Dateadd(wk,datediff(wk,0,getdate()),-1) )x<oRHx]
Dateadd(wk,datediff(wk,0,getdate()),6) )k~{p;Ke
Dateadd(mm,datediff(mm,0,getdate()),0) 1m{c8Z.h/d
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) dq4t@:\o0
Dateadd(yy,datediff(yy,0,getdate()),0) -s_=4U,
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) zcE`.)y
上面的SQL代码只是一个时间段 p|`[8uY?
Dateadd(wk,datediff(wk,0,getdate()),-1) 8ioxb`U
Dateadd(wk,datediff(wk,0,getdate()),6) Hw\hTTK
就是表示本周时间段. (>,}C/-UG
下面的SQL的条件部分,就是查询时间段在本周范围内的: O<\h_
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) qKjUp"
而在存储过程中 aYmN'
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )e?6 Ncy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6j6P&[