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。 )vGRfFjw_
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一、基础 KS(T%mk\
1、说明:创建数据库 sQihyq6U;
CREATE DATABASE database-name J;q3
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2、说明:删除数据库 ]P<&CEk
drop database dbname xI:;%5{LN
3、说明:备份sql server <JH0 &
--- 创建 备份数据的 device "l +Jx|h\
USE master @1Zf&'/6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'T|.<u@~
--- 开始 备份 XcfTE
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BACKUP DATABASE pubs TO testBack l]v
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4、说明:创建新表 Rb#Z\e}e-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]r"{G*1Q
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根据已有的表创建新表: RXx
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A:create table tab_new like tab_old (使用旧表创建新表) [>_(q|A6+
B:create table tab_new as select col1,col2... from tab_old definition only )If[pw@j
5、说明:删除新表 ir,Zc\C
drop table tabname =C3l:pGMB;
6、说明:增加一个列 x-Mp6
Alter table tabname add column col type 6o1.?t?
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。 QdW%5lM+
7、说明:添加主键: Alter table tabname add primary key(col) bNaJ{Dm$R
说明:删除主键: Alter table tabname drop primary key(col) 4a2&kIn
8、说明:创建索引:create [unique] index idxname on tabname(col....) KP<J~+_ik
删除索引:drop index idxname @Qc['V)
注:索引是不可更改的,想更改必须删除重新建。 ~C!vfPC
9、说明:创建视图:create view viewname as select statement B|GJboQ
删除视图:drop view viewname Fsq S)
10、说明:几个简单的基本的sql语句 IG9Q~7@
选择:select * from table1 where 范围 ]-PF? 8
插入:insert into table1(field1,field2) values(value1,value2) h0^V!.-5
删除:delete from table1 where 范围 caj)
更新:update table1 set field1=value1 where 范围 nW drVT$
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 10}Zoq|)n
排序:select * from table1 order by field1,field2 [desc] hCxL4LrF
总数:select count as totalcount from table1 g:o\ r
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求和:select sum(field1) as sumvalue from table1 -O_UpjR;
平均:select avg(field1) as avgvalue from table1 !w)Mm P Xb
最大:select max(field1) as maxvalue from table1 #JLDj(a?
最小:select min(field1) as minvalue from table1 v"F0$c
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11、说明:几个高级查询运算词 xwRnrWd^6
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A: UNION 运算符 NI^Y%N
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 lMm-K%(2
B: EXCEPT 运算符 yZ!Eu#81
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 )$]+R?v
C: INTERSECT 运算符 } 1XLe
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。 j{;3+LCo*
注:使用运算词的几个查询结果行必须是一致的。 >6kWmXK[
12、说明:使用外连接 3x=F
A、left outer join: _E30t( _.
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。 3tm z2JIb
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 x#YOz7.
B:right outer join: Czci6Lz
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。 Sm Ei _u]'
C:full outer join: H_AV 3
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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。 n]$vCP
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二、提升 ./fEx
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) C3b'Q
法一:select * into b from a where 1<>1 y\S7oD(OR
法二:select top 0 * into b from a 5~44R@`
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) v =?V{"wk!
insert into b(a, b, c) select d,e,f from b; FI/YJ@21
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) eY(usK
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 U1"t|KW8
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @B'Mu:|f
4、说明:子查询(表名1:a 表名2:b) V!opnLatYS
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) -DuiK:mp
5、说明:显示文章、提交人和最后回复时间 {//F>5~[
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8uGPyH
6、说明:外连接查询(表名1:a 表名2:b) Ffxk] o&%c
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c qIqk@u
7、说明:在线视图查询(表名1:a ) oOL3O@)w>
select * from (SELECT a,b,c FROM a) T where t.a > 1; Z~,.l
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 pS<b|wu?f
select * from table1 where time between time1 and time2 M|v.5l#
select a,b,c, from table1 where a not between 数值1 and 数值2 ipzUF o<w
9、说明:in 的使用方法 u:S@'z>
select * from table1 where a [not] in ('值1','值2','值4','值6') XOeh![eMX
10、说明:两张关联表,删除主表中已经在副表中没有的信息 hv"toszj\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \Zh)oUHd
11、说明:四表联查问题: __V]HcP;
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 ..... dI 5sqM:
12、说明:日程安排提前五分钟提醒 /-hF<oNQ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )>Q 2G/@
13、说明:一条sql 语句搞定数据库分页 dq8 /^1P
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 p;7 4+q
14、说明:前10条记录 kR6 t
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select top 10 * form table1 where 范围 PPqTmx5S
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.) j^ _I{
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3N
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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 4y1>!~f
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7>zKW?
17、说明:随机取出10条数据 @*uX[)
select top 10 * from tablename order by newid() lQsQRp
18、说明:随机选择记录 vaf9b}FL
select newid() hY1|qp
19、说明:删除重复记录 eTF8B<?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) PD}R7[".>
20、说明:列出数据库里所有的表名 _RW[]MN3*
select name from sysobjects where type='U' psZeu*/r
21、说明:列出表里的所有的 ).]m@g:ew
select name from syscolumns where id=object_id('TableName') {\aSEE/'
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。 @|GeR
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 jSFN/C.9h
显示结果: )T64(_TE
type vender pcs da2[
电脑 A 1
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电脑 A 1 zkp
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光盘 B 2 |g7h#F~
光盘 A 2 i)2))C
手机 B 3 Ft7a\vn*B
手机 C 3 `oMeR]~
23、说明:初始化表table1 ya{>=
TRUNCATE TABLE table1 Z0=m:h
24、说明:选择从10到15的记录 +hg\DqO^M
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Y/S3)o
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三、技巧 IPO[J^#Me
1、1=1,1=2的使用,在SQL语句组合时用的较多 >$mSFJz5S
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Q@2tT&eL
如: GVEWd/:X(
if @strWhere !='' u!uDu,y
begin Y(y9l{'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W"kw>JEt
end VM]IL%AN
else vs1Sh?O
begin cY2-T#rL
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' N}Ks[2
end }iSakq'
我们可以直接写成 ,w%oSlOu
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere z9ShP&^4[
2、收缩数据库 eUkoVr
--重建索引 JQ_gM._3
DBCC REINDEX {%_j~
DBCC INDEXDEFRAG CjQ"o Qw
--收缩数据和日志 5FSv"=
DBCC SHRINKDB , Ln
DBCC SHRINKFILE Tq84Fn!HJ>
3、压缩数据库 _g 4/%
dbcc shrinkdatabase(dbname) (L5'rNk
4、转移数据库给新用户以已存在用户权限 eFSC^
exec sp_change_users_login 'update_one','newname','oldname' AD@PNM
go u7"VeTz
5、检查备份集 Tj=dL
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' _GO+fB/Q1
6、修复数据库 Zva
ALTER DATABASE [dvbbs] SET SINGLE_USER jBv$^L
GO 2 1~7{#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK b%;59^4AjD
GO JYd7@Msfc
ALTER DATABASE [dvbbs] SET MULTI_USER b;L>%;
GO }E5#X R
7、日志清除 ay(!H~q_U
SET NOCOUNT ON )E:,V~< 8
DECLARE @LogicalFileName sysname, Iz)hz9k
@MaxMinutes INT, P/pjy
@NewSize INT y5/6nvH_6
USE tablename -- 要操作的数据库名 qijcS2E6S
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `OP>(bU0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. lB!vF ~A&
@NewSize = 1 -- 你想设定的日志文件的大小(M) lmQ 6X
-- Setup / initialize #jZ@l3
DECLARE @OriginalSize int {KDgK
SELECT @OriginalSize = size 9U)t@b
FROM sysfiles ahtYSz_FM
WHERE name = @LogicalFileName -@L's{J{M
SELECT 'Original Size of ' + db_name() + ' LOG is ' + y|.fR>5
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + CofH}-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ns#~}2"d
FROM sysfiles _Dj<Eu_
WHERE name = @LogicalFileName 23-t$y]
CREATE TABLE DummyTrans &G/|lv>j
(DummyColumn char (8000) not null) u<]mv
DECLARE @Counter INT, XocsSs
@StartTime DATETIME, f>r3$WKj
@TruncLog VARCHAR(255) ^IGyuj0]jG
SELECT @StartTime = GETDATE(), %X9b=%'+
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \V^*44+
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) jJVT_8J
EXEC (@TruncLog) C.>
-- Wrap the log if necessary. i<m$#6<Z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +~d1;0l|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |qlS6Aln
AND (@OriginalSize * 8 /1024) > @NewSize 8lOI\-
BEGIN -- Outer loop. w,Z"W;|
SELECT @Counter = 0 kT^*>=1
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) )4ilCS&
BEGIN -- update k(EMp1[:nN
INSERT DummyTrans VALUES ('Fill Log') ALd]1a&
DELETE DummyTrans ]jc_=I6)
SELECT @Counter = @Counter + 1 Xlv#=@;O]
END -\kXH"%
EXEC (@TruncLog) a jQqj.
END @Y
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + $J"%I$%X=
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I1)-,/nEjg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {pDTy7!Hs
FROM sysfiles UP;Q= t
WHERE name = @LogicalFileName ivzAlwP
DROP TABLE DummyTrans hOPe^e"
SET NOCOUNT OFF d(fPECv(
8、说明:更改某个表 gF[6c`-s
exec sp_changeobjectowner 'tablename','dbo' b]*X<,p
9、存储更改全部表 hr$Sa
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?j/kOD0
@OldOwner as NVARCHAR(128), u 1ZJHry
@NewOwner as NVARCHAR(128) QqtC`H\
AS Hz?!BV0
DECLARE @Name as NVARCHAR(128) >z=Ou<,
DECLARE @Owner as NVARCHAR(128) ptpW41t}^
DECLARE @OwnerName as NVARCHAR(128) |3{+6cg
DECLARE curObject CURSOR FOR f.oP
select 'Name' = name, {l2N&
'Owner' = user_name(uid) j z~[5m}J
from sysobjects ;8P_av}C
where user_name(uid)=@OldOwner o]Wz6L
order by name Vkr`17`G
OPEN curObject '{[!j6wt\
FETCH NEXT FROM curObject INTO @Name, @Owner y" ^yYO
WHILE(@@FETCH_STATUS=0) Q.,DZp
BEGIN (0i'Nb"
if @Owner=@OldOwner n%/i:Whs
begin V+lRi"m?|
set @OwnerName = @OldOwner + '.' + rtrim(@Name) w[(n>
exec sp_changeobjectowner @OwnerName, @NewOwner {-@~Q.&}v
end 5YiZ-CQ>
-- select @name,@NewOwner,@OldOwner [p ii
FETCH NEXT FROM curObject INTO @Name, @Owner 2sKG(^=Z
END lhqQCV
close curObject XRa(sXA3
deallocate curObject pW\z\o/2
GO -bypuMQ-p
10、SQL SERVER中直接循环写入数据 *URdd,){i
declare @i int eZg$AOpU
set @i=1 EeCFII
while @i<30 iTh
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begin H]s4% 9T
insert into test (userid) values(@i) #?9Q{0e
set @i=@i+1 <uZPqi||
end !@u&{"{`
小记存储过程中经常用到的本周,本月,本年函数 Sx8l<X
Dateadd(wk,datediff(wk,0,getdate()),-1) &p5&=zV}
Dateadd(wk,datediff(wk,0,getdate()),6) E0QPE5_
Dateadd(mm,datediff(mm,0,getdate()),0) @(-yrU
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +?;j&p
Dateadd(yy,datediff(yy,0,getdate()),0) .o}%~g <d
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) S'o ]=&
上面的SQL代码只是一个时间段 -kl;!:'.3
Dateadd(wk,datediff(wk,0,getdate()),-1) <_9!
Dateadd(wk,datediff(wk,0,getdate()),6) s~^*+kq
就是表示本周时间段. td >,TW=A*
下面的SQL的条件部分,就是查询时间段在本周范围内的: .Gh%p`<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) lop uf/U0
而在存储过程中 B{p4G`$i1
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) yRC3
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6xarYh(