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。 " ?n~ /9`
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一、基础 i$ "B
1、说明:创建数据库 FtT+Q$q=
CREATE DATABASE database-name V 1;n5YL
2、说明:删除数据库 Jc:*X4-'
drop database dbname Q_qc_IcM y
3、说明:备份sql server mp%i(Y"vp
--- 创建 备份数据的 device o1-Zh!*a*
USE master <JDkvpckx.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' OV Iu&6#
--- 开始 备份 a*KB'u6&
BACKUP DATABASE pubs TO testBack cPkN)+K
4、说明:创建新表 dy#dug6j
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z#nj[r!l}
根据已有的表创建新表: bsR&%C
A:create table tab_new like tab_old (使用旧表创建新表) kT!FC0E{
B:create table tab_new as select col1,col2... from tab_old definition only D 0\
5、说明:删除新表 jvCk+n[
drop table tabname VO/"
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6、说明:增加一个列 mS0*%[S {
Alter table tabname add column col type ?UQE;0 B
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。 q?e97 a
7、说明:添加主键: Alter table tabname add primary key(col) ~g~z"!K
说明:删除主键: Alter table tabname drop primary key(col) }vPDCUZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) d* 7 Tjs{\
删除索引:drop index idxname z9u"?vdA
注:索引是不可更改的,想更改必须删除重新建。 XM>ByfD{
9、说明:创建视图:create view viewname as select statement O83vPK
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删除视图:drop view viewname ^1Y0JQ
10、说明:几个简单的基本的sql语句 VLkK6W.u
选择:select * from table1 where 范围 ;:a7rN"(
插入:insert into table1(field1,field2) values(value1,value2) +wgNuj0=*
删除:delete from table1 where 范围 gBf%9F
更新:update table1 set field1=value1 where 范围 {{SeD:hx
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! l%rwJLN1
排序:select * from table1 order by field1,field2 [desc] /t(dhz&xN
总数:select count as totalcount from table1 b_z;^y~
求和:select sum(field1) as sumvalue from table1 %7z
平均:select avg(field1) as avgvalue from table1 jun>(7
最大:select max(field1) as maxvalue from table1 uJ {N?
最小:select min(field1) as minvalue from table1 V2V^*9(wu@
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11、说明:几个高级查询运算词 q;InFV3rv
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A: UNION 运算符 ;sS N
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。 tHJ#2X#Y.
B: EXCEPT 运算符 "fL:scq@0
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。 th2a'y=0
C: INTERSECT 运算符 }pTy mAN
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。 *U)!9DvA
注:使用运算词的几个查询结果行必须是一致的。 h7wm xa;
12、说明:使用外连接 Yq $(Ex
A、left outer join: vLXN{ ]
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 `/Zi=.rr
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c tz6d}$
B:right outer join: x3MV"hm2
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。 L/_OgL]YdI
C:full outer join: Ir_K83VM
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。 ;SEH|_/
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二、提升 o>';-} E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 2$jTj<.K
法一:select * into b from a where 1<>1 !gWV4vC
法二:select top 0 * into b from a oL2|@WNj,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }`{aeVHT
insert into b(a, b, c) select d,e,f from b; {]n5h#c 5*
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) @K7#}7,t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ^EPM~cEY\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. p%jl-CC1
4、说明:子查询(表名1:a 表名2:b) 7^A;.x
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) I;S[Ft8d
5、说明:显示文章、提交人和最后回复时间 $RuJm\f
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b :CNHN2 J
6、说明:外连接查询(表名1:a 表名2:b) a<B[~J 4i
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c X@*$3z#Z
7、说明:在线视图查询(表名1:a ) $o?Wum
select * from (SELECT a,b,c FROM a) T where t.a > 1; s"*zyLUUo
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 1NtN-o)N?
select * from table1 where time between time1 and time2 >t<FG2
select a,b,c, from table1 where a not between 数值1 and 数值2 S>Z V8
9、说明:in 的使用方法 Ysz{~E'
select * from table1 where a [not] in ('值1','值2','值4','值6') )3V5P%Q
10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Rf+ogLa=
11、说明:四表联查问题: %`t;5kmR
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 ..... @V
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12、说明:日程安排提前五分钟提醒 ]!E|5=q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ):
13、说明:一条sql 语句搞定数据库分页 R+
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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 "6Hka{
14、说明:前10条记录 CLg;
select top 10 * form table1 where 范围 Yc/Nz(m
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.) =toqEm~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5P9hm[
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 c{Nk"gEfRA
(select a from tableA ) except (select a from tableB) except (select a from tableC) O['gp~P"
17、说明:随机取出10条数据 .cdm@_Ls
select top 10 * from tablename order by newid() OW<i"?0
18、说明:随机选择记录 k6_RJ8I
select newid() HeZ! "^w
19、说明:删除重复记录 }#Z Q\[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) RY2`v
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20、说明:列出数据库里所有的表名 *-(J$4RNz
select name from sysobjects where type='U' n_Px=s!1p@
21、说明:列出表里的所有的 lpQsmd#
select name from syscolumns where id=object_id('TableName') B @H.O!
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=abyD
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 3@kiUbq7Eu
显示结果: ]&`_5pS
type vender pcs 6q RZ#MC
电脑 A 1 7afD^H%
电脑 A 1 + |Z1U$0g
光盘 B 2 /-TJtR4>
光盘 A 2 ,ilVt
手机 B 3 `VCU`Y
手机 C 3 n8DWA`[ib
23、说明:初始化表table1 9JV(}v5[
TRUNCATE TABLE table1 ]X?~Cz/wl
24、说明:选择从10到15的记录 ^} P|L
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc OM*N) *
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三、技巧 *|h-iA+9
1、1=1,1=2的使用,在SQL语句组合时用的较多 zA=gDuy3@
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: AmNmhcN
if @strWhere !='' R,-y
begin 9!zUv:;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =PWh,lWS
end Z;M]^?
else :j)H;@[I
begin S^?
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' jFf2( AR
end ( >zXapb2
我们可以直接写成 qMD 6LWJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *T'
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2、收缩数据库 z1XFc*5
--重建索引 kFZw"5hb
DBCC REINDEX C2NJrg4(
DBCC INDEXDEFRAG 12n5{'H2%
--收缩数据和日志 p8o
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DBCC SHRINKDB jU
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DBCC SHRINKFILE ;
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3、压缩数据库 gO_{(\w*
dbcc shrinkdatabase(dbname) 6 "U&i9
4、转移数据库给新用户以已存在用户权限 [h SE^
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exec sp_change_users_login 'update_one','newname','oldname' ;A7HEx
go Ymkk"y.w
5、检查备份集 <yz)iCU?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hG .>>
6、修复数据库 3CK4a,]Dm
ALTER DATABASE [dvbbs] SET SINGLE_USER _doX&*9u
GO Ve#VGlI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Vui5Z K
GO e@"1W
ALTER DATABASE [dvbbs] SET MULTI_USER 6Ko[[?Lf[
GO 6*9hAnH
7、日志清除 %
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SET NOCOUNT ON iD+Q\l;%
DECLARE @LogicalFileName sysname, b3N>RPsHS
@MaxMinutes INT, :M)B#@ c=
@NewSize INT 6C@,&2<yK
USE tablename -- 要操作的数据库名 g
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *ci,;-*C
@MaxMinutes = 10, -- Limit on time allowed to wrap log. w|!>>W6J
@NewSize = 1 -- 你想设定的日志文件的大小(M) 12BTZ
-- Setup / initialize 0j\?zt?
DECLARE @OriginalSize int A@-nn]
SELECT @OriginalSize = size xvOGE]n
FROM sysfiles l&2A]5C
WHERE name = @LogicalFileName 5RCQ<1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + d%VG@./xq
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + T8+A`z=tSb
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' . #`lW7
FROM sysfiles %SuEfCM
WHERE name = @LogicalFileName Njsz=
CREATE TABLE DummyTrans Tn2nd
(DummyColumn char (8000) not null) >fRI^Q,
DECLARE @Counter INT, :%cL(',Q
@StartTime DATETIME, ~`)`Ip
@TruncLog VARCHAR(255) &.D3f"
SELECT @StartTime = GETDATE(), MT9c:7}[&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' EEFM1asJf
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o5?f]Uq5 ,
EXEC (@TruncLog) b)RU+9x &
-- Wrap the log if necessary. OEmz`JJ67
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #ky]@vyO
AND (@OriginalSize * 8 /1024) > @NewSize l6Wa~ E
BEGIN -- Outer loop. 2 Pn
SELECT @Counter = 0 /T&z
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) TD:NL4dm
BEGIN -- update l]D?S]{a
INSERT DummyTrans VALUES ('Fill Log') Lh.?G#E M
DELETE DummyTrans b@j**O>[q)
SELECT @Counter = @Counter + 1 5>+>=)*
END ZD\`~I|gp
EXEC (@TruncLog) COPH)Bdq.
END Y-\/Y*;cd
SELECT 'Final Size of ' + db_name() + ' LOG is ' + aC:Sy^Tf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 5q?2?j/h
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' D#|+PG7
FROM sysfiles ))f%3_H
WHERE name = @LogicalFileName %B+W#Q`
DROP TABLE DummyTrans 6U[`CGL66
SET NOCOUNT OFF t=M:L[bis;
8、说明:更改某个表 R{Q*"sf
exec sp_changeobjectowner 'tablename','dbo' U5Say3r
9、存储更改全部表 R&}"En`$s
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch A*#.7Np!"
@OldOwner as NVARCHAR(128), 1sp>UBG
@NewOwner as NVARCHAR(128) 6vp\~J
AS G?$|aQ0j
DECLARE @Name as NVARCHAR(128) "]h4L
DECLARE @Owner as NVARCHAR(128) ` b a}6D
DECLARE @OwnerName as NVARCHAR(128) 6)63Yp(
DECLARE curObject CURSOR FOR [r,a0s
select 'Name' = name, *y
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'Owner' = user_name(uid) s&:LY"[`
from sysobjects P__JN\{9
where user_name(uid)=@OldOwner 8q9HQ4dsL
order by name Pf&\2_H3s9
OPEN curObject L-z37kG^
FETCH NEXT FROM curObject INTO @Name, @Owner ?HwW~aO
WHILE(@@FETCH_STATUS=0) 6UK{0\0
BEGIN mYLqT$t.+
if @Owner=@OldOwner l_bvwo
begin h8@8Qw
set @OwnerName = @OldOwner + '.' + rtrim(@Name) =kvfe" N0e
exec sp_changeobjectowner @OwnerName, @NewOwner HE
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end g-`HKoKe
-- select @name,@NewOwner,@OldOwner C
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FETCH NEXT FROM curObject INTO @Name, @Owner hu}`,2
END V5w00s5?%
close curObject tGHZU^B:}
deallocate curObject `x%v&>
GO "FA&Qm0
10、SQL SERVER中直接循环写入数据 R
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declare @i int JGQlx-qv
set @i=1 M#o.$+Uh
while @i<30 NAd|n+[d
begin 4qMqAT
insert into test (userid) values(@i) b[&A,ZPh$@
set @i=@i+1 I&JVY8'
end >iD&n4TK
小记存储过程中经常用到的本周,本月,本年函数 DM
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Dateadd(wk,datediff(wk,0,getdate()),-1) sf{rs*bgp
Dateadd(wk,datediff(wk,0,getdate()),6) ~ [L4,q
Dateadd(mm,datediff(mm,0,getdate()),0) l&3f<e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) `x=W)o
}
Dateadd(yy,datediff(yy,0,getdate()),0) ]WlE9z7:8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) /d; C)%$
上面的SQL代码只是一个时间段 Gx Z'" x
Dateadd(wk,datediff(wk,0,getdate()),-1) TG4?"0`I5
Dateadd(wk,datediff(wk,0,getdate()),6) k#mQLv
就是表示本周时间段. 1>hY!nG h
下面的SQL的条件部分,就是查询时间段在本周范围内的: X(sHFVU+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Hy4c{Ij
而在存储过程中 kA3nhBH
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 5(BB`)
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) q@K8,=/.#