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。 r_R|.fl<[
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一、基础 /n:s9eq
1、说明:创建数据库 \DfvNeF
CREATE DATABASE database-name .Sb|+[{
2、说明:删除数据库 4; j#7
drop database dbname 9K)OQDv%6D
3、说明:备份sql server fV;&Ag*ZiV
--- 创建 备份数据的 device 2-{8+*_'
USE master \8<bb<`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]YwIuz6 ]
--- 开始 备份 E!ZDqq
BACKUP DATABASE pubs TO testBack iRPd=)
4、说明:创建新表 hbN*_[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SHhg&~B
根据已有的表创建新表: {_Ke'"
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A:create table tab_new like tab_old (使用旧表创建新表) La3f{;|u5M
B:create table tab_new as select col1,col2... from tab_old definition only ~L 4"t_-
5、说明:删除新表 ?VReKv1\
drop table tabname J7mT&U&Ru
6、说明:增加一个列 NB16O!r
Alter table tabname add column col type 8xL-j2w
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。 a@m>S$S
7、说明:添加主键: Alter table tabname add primary key(col) XFd[>U<X
说明:删除主键: Alter table tabname drop primary key(col) %f,
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8、说明:创建索引:create [unique] index idxname on tabname(col....) m*["
删除索引:drop index idxname %OW[rbE.
注:索引是不可更改的,想更改必须删除重新建。 '!En,*'IS
9、说明:创建视图:create view viewname as select statement {V:?r
删除视图:drop view viewname f~"3#MaV
10、说明:几个简单的基本的sql语句 @tp/0E?
选择:select * from table1 where 范围 o#w6]Fmc
插入:insert into table1(field1,field2) values(value1,value2) \Z57U NI
删除:delete from table1 where 范围 #<se0CJB
更新:update table1 set field1=value1 where 范围 }S%a]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! s-k-|4
排序:select * from table1 order by field1,field2 [desc] 12cfqIo9
总数:select count as totalcount from table1 >,1'[)_
求和:select sum(field1) as sumvalue from table1 <pi q?:ac
平均:select avg(field1) as avgvalue from table1 zRsA[F#
最大:select max(field1) as maxvalue from table1 }eB\k,7L
最小:select min(field1) as minvalue from table1 Ya=QN<
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11、说明:几个高级查询运算词 H&%=>hyX
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A: UNION 运算符 zJ &qR
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。 i|=}zR
B: EXCEPT 运算符 Sw(%j1uL
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。 ydlH6 >
C: INTERSECT 运算符 ]kc_wFT<
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。 BRH:5h
注:使用运算词的几个查询结果行必须是一致的。 vtr:{
12、说明:使用外连接 vqL{~tR
A、left outer join: sW=@G'}3
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。 nPv2: x
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 mM}|x~\R
B:right outer join: h8S%Q|-
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。 b^A&K@[W#,
C:full outer join: 0BE%~W
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。 2%WZ-l!i
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二、提升 #0 ^QUOp
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) /$q;-/DnTZ
法一:select * into b from a where 1<>1 YQ?|Vb
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法二:select top 0 * into b from a W#??fae
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _X@:-_
insert into b(a, b, c) select d,e,f from b; MjG.Ili$m
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 5^%^8o
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 O<%U*:B
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0<>iMr D
4、说明:子查询(表名1:a 表名2:b) gXf_~zxS
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) gR?3)m
5、说明:显示文章、提交人和最后回复时间 E}a3. 6)p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `SIJszqc
6、说明:外连接查询(表名1:a 表名2:b) AM Rj N;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6^
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7、说明:在线视图查询(表名1:a ) Xi0/Wb h\
select * from (SELECT a,b,c FROM a) T where t.a > 1; XK&#K? M
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 O|gb{
select * from table1 where time between time1 and time2 Sb{S^w\m0
select a,b,c, from table1 where a not between 数值1 and 数值2 )6AOP-M.9
9、说明:in 的使用方法 W<9GwMU
select * from table1 where a [not] in ('值1','值2','值4','值6') T!;<Fy"p
10、说明:两张关联表,删除主表中已经在副表中没有的信息 auGt>,Zj\Q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;=e A2
11、说明:四表联查问题: j*6!7u.,K
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... R6M@pO
12、说明:日程安排提前五分钟提醒 ]|732Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 gi"v${R
13、说明:一条sql 语句搞定数据库分页 4CN8>J'-
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 zu;Yw=cM)
14、说明:前10条记录 ^_<pc|1
select top 10 * form table1 where 范围 />n0&~k[h
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.) 3K#e]zoI
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6 a$%
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 tB1Qr**
(select a from tableA ) except (select a from tableB) except (select a from tableC) _IY)<'d
17、说明:随机取出10条数据 tKJ)'v?
select top 10 * from tablename order by newid() N Z.aI{
18、说明:随机选择记录 bFflA
select newid() ,2?C^gxt
19、说明:删除重复记录 } g
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #}jf TM
20、说明:列出数据库里所有的表名 xK_$^c.
select name from sysobjects where type='U' :z"Uw*
21、说明:列出表里的所有的 E8-p
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select name from syscolumns where id=object_id('TableName') "#m*`n
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。 %/>_o{"hw
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 q#WqU8~Y
显示结果: ?2G^6>O`
type vender pcs !$d:k|b
电脑 A 1 tL
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电脑 A 1 ' u0{h
光盘 B 2 HX
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光盘 A 2 +SP5+"y@
手机 B 3 mybDK'EW
手机 C 3 9ge$)q@3
23、说明:初始化表table1 /\\C&Px
TRUNCATE TABLE table1 cu""vtK
24、说明:选择从10到15的记录 ~S=hxKI
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc fc\hQXYv
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三、技巧 s%/0WW0y^
1、1=1,1=2的使用,在SQL语句组合时用的较多 rAQ^:q
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ''WX
如: NuXU2w~
if @strWhere !='' F,EHZ,<V
begin 1-JWqV(#?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }Rf }
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end '7=*n_l
else RhDa`kV%t
begin (8>k_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' %EVg.k$
end OZv&{_b_
我们可以直接写成 UcK!v*3E
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^^ ?ECnpcU
2、收缩数据库 979L] H#
--重建索引 e%f8|3<6
DBCC REINDEX B
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DBCC INDEXDEFRAG Q2#)Jx\6!
--收缩数据和日志 $hN!DHz
DBCC SHRINKDB ,
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DBCC SHRINKFILE nF//y}
3、压缩数据库 4<O[d
dbcc shrinkdatabase(dbname) AM }OLHj
4、转移数据库给新用户以已存在用户权限 rFmE6{4:p
exec sp_change_users_login 'update_one','newname','oldname' ph|3M<q6
go )
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5、检查备份集 4mPg; n
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 1`)R#$h
6、修复数据库 MQ,2v.
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ALTER DATABASE [dvbbs] SET SINGLE_USER wDSU~\
GO p<J/J.E
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK "fmJ;W;#1
GO ?c43cYb
ALTER DATABASE [dvbbs] SET MULTI_USER >4ALF[oH1J
GO ]9x30UXLwD
7、日志清除 Nls|R
SET NOCOUNT ON LXx3
DECLARE @LogicalFileName sysname, vR`KRI`{
@MaxMinutes INT, 4b<:67
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@NewSize INT }y0UyOa{C
USE tablename -- 要操作的数据库名 20Rgw
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ; aMMIp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]#J]f
@NewSize = 1 -- 你想设定的日志文件的大小(M) ^y h
-- Setup / initialize zU}0AVlIL:
DECLARE @OriginalSize int Nd( $s[
SELECT @OriginalSize = size BE m%x0y
FROM sysfiles <vj&e(D^
WHERE name = @LogicalFileName I
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + z3$PrK%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AU7c =
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [PU.lRq
FROM sysfiles 7%F9.h
WHERE name = @LogicalFileName $AX!L+<!
CREATE TABLE DummyTrans u4Xrvfb,
(DummyColumn char (8000) not null) ZBnf?fU
DECLARE @Counter INT, [qb#>P2G3
@StartTime DATETIME, \@80Z5?n
@TruncLog VARCHAR(255) 1YA_`_@w
SELECT @StartTime = GETDATE(), MU^7(s="
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -VESe}c:nQ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) i`^`^Ka
EXEC (@TruncLog) )hHkaI>eYv
-- Wrap the log if necessary. F(8>"(C
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired c8sY#I
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) a(X?N.w
AND (@OriginalSize * 8 /1024) > @NewSize BC0T[o(f8
BEGIN -- Outer loop. `":ch9rK
SELECT @Counter = 0 dE*n!@
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &P%3'c}G
BEGIN -- update Ch`XwLY9
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans xS` %3+|
SELECT @Counter = @Counter + 1 Z,Z34:-
END M?4)U"_VE
EXEC (@TruncLog) nBGFa
END q@ >s#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >_1*/o
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + #;Y JR9VN
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' }"<|.[V)
FROM sysfiles s% "MaDz
WHERE name = @LogicalFileName I)AV
DROP TABLE DummyTrans 5Cd>p<
SET NOCOUNT OFF I=wP"(2
8、说明:更改某个表 @eN x:}
exec sp_changeobjectowner 'tablename','dbo' lkK+Fm
9、存储更改全部表 r>S?,qr
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7z"xjA
@OldOwner as NVARCHAR(128), nsqs*$
@NewOwner as NVARCHAR(128) mvI[=e*
AS V?v,q'? $
DECLARE @Name as NVARCHAR(128) (b Q1,y
DECLARE @Owner as NVARCHAR(128) I|JMkP
DECLARE @OwnerName as NVARCHAR(128) >[=q9k
DECLARE curObject CURSOR FOR W6D|Rr.q
select 'Name' = name, 6~sb8pK.=
'Owner' = user_name(uid) 7</&=lly
from sysobjects Y25S:XHk9
where user_name(uid)=@OldOwner ~]DGf(
order by name wxXp(o(
OPEN curObject AoL4#.r3H
FETCH NEXT FROM curObject INTO @Name, @Owner A^2VH$j]+
WHILE(@@FETCH_STATUS=0) :3$WY<
BEGIN nnX,_5s
if @Owner=@OldOwner -
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begin yHl1:cf(y
set @OwnerName = @OldOwner + '.' + rtrim(@Name) (,`ypD +3q
exec sp_changeobjectowner @OwnerName, @NewOwner bR6.Xdt.n
end 1+RG@Cp
-- select @name,@NewOwner,@OldOwner 2e zQX2q
FETCH NEXT FROM curObject INTO @Name, @Owner D\ ]gIXg
END LFob1HH*8
close curObject ~h6aw
deallocate curObject "qUUH4mR`
GO q'77BRD3
10、SQL SERVER中直接循环写入数据 k/YEUC5
declare @i int 9l9nT
set @i=1 WY#A9i5Ge
while @i<30 j2SJ4tB /
begin >4`("#
insert into test (userid) values(@i) $Zp\^cIE+
set @i=@i+1 tM]~^U
end R)d1]k8
小记存储过程中经常用到的本周,本月,本年函数 5*u0VabC<
Dateadd(wk,datediff(wk,0,getdate()),-1) &U ]L@]x
Dateadd(wk,datediff(wk,0,getdate()),6) s~$ZTzV
Dateadd(mm,datediff(mm,0,getdate()),0) [ !/u,
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) :}}5TJ wG
Dateadd(yy,datediff(yy,0,getdate()),0) (:Rj:8{
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :@{(^}N8u
上面的SQL代码只是一个时间段 %719h>$
Dateadd(wk,datediff(wk,0,getdate()),-1) `z%f@/:fG
Dateadd(wk,datediff(wk,0,getdate()),6) Z`<S_PPz
就是表示本周时间段. fqA\Rp6Z
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4;'o`K~*
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Y3+DTR0|'
而在存储过程中 m(SGE,("w
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) P2pdXNV
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @ofivCc<%