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。 y!dw{Lz
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一、基础 +1a3^A\
1、说明:创建数据库 %Z+**>1J
CREATE DATABASE database-name Kx?.g#>U;
2、说明:删除数据库 aNn4j_V(
drop database dbname F [Lg,}
3、说明:备份sql server d-C%R9
--- 创建 备份数据的 device YV _ 7 .+A
USE master Z4X, D`s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L|Xg4Z
--- 开始 备份 r7sA;Y\
BACKUP DATABASE pubs TO testBack .hM t:BMf*
4、说明:创建新表 1 +s;a]-C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ?(Ua+*b
根据已有的表创建新表: q'/o=De
A:create table tab_new like tab_old (使用旧表创建新表) |g>Q3E
B:create table tab_new as select col1,col2... from tab_old definition only "hQGk
5、说明:删除新表 hj&~Dn(
drop table tabname 1l/t|M^I
6、说明:增加一个列 Z^}[CQ&Am
Alter table tabname add column col type (/0dtJ
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。 fdWqc_
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) )7]yzc
8、说明:创建索引:create [unique] index idxname on tabname(col....) -Bl^TT
删除索引:drop index idxname :5['V#(o
注:索引是不可更改的,想更改必须删除重新建。 98)C
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9、说明:创建视图:create view viewname as select statement yf;TIh%)=
删除视图:drop view viewname ML MetRP
10、说明:几个简单的基本的sql语句 {NQCe0S+p
选择:select * from table1 where 范围 D)pTE?@W'
插入:insert into table1(field1,field2) values(value1,value2) gq;>DY]
删除:delete from table1 where 范围 o$Ylqb#
更新:update table1 set field1=value1 where 范围 Be6+YM5Cl
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! O) TS$
排序:select * from table1 order by field1,field2 [desc] ?;_>BX|Zjl
总数:select count as totalcount from table1 rQ_]%ies8
求和:select sum(field1) as sumvalue from table1 n((A:b
平均:select avg(field1) as avgvalue from table1 %$kd`Rl}
最大:select max(field1) as maxvalue from table1 w3"L5;oH
最小:select min(field1) as minvalue from table1 w~'}uh
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11、说明:几个高级查询运算词 dCS f$5
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A: UNION 运算符 7)Vbp--b#
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。 Ncsh{.
B: EXCEPT 运算符 ;9WUt,R
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。 W7b
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C: INTERSECT 运算符 A6 .wXv,
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。 $.kJBRgV*
注:使用运算词的几个查询结果行必须是一致的。 L -:@Om!
12、说明:使用外连接 m2"e ]I
A、left outer join: [>r0
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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。 :b(W&iBWhI
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 {:("oK6w
B:right outer join: QRK\74'uY
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。 oQ,<Yx%E3
C:full outer join: v*qbzW`
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。 -aVC`
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二、提升 $,]U~7S
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~Gz9pBv1
法一:select * into b from a where 1<>1 e3W~6P
法二:select top 0 * into b from a j*gJP
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kE.4 #
insert into b(a, b, c) select d,e,f from b; TwI s_r:
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) K)wWqC.
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 aA52Li
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. |idw?qCn
4、说明:子查询(表名1:a 表名2:b) OqDP{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) fglfnx0{
5、说明:显示文章、提交人和最后回复时间 Fz,jnV9=j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ^i Jyo&I
6、说明:外连接查询(表名1:a 表名2:b) {4,],0bjx/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c &Q;sbI}
7、说明:在线视图查询(表名1:a ) ;m#4Q6k)V?
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;aWk-
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 w-#
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select * from table1 where time between time1 and time2 5|*`} ;/y
select a,b,c, from table1 where a not between 数值1 and 数值2 *j&)=8Y|
9、说明:in 的使用方法 ;*<R~HJt
select * from table1 where a [not] in ('值1','值2','值4','值6') 1S!}su,uH
10、说明:两张关联表,删除主表中已经在副表中没有的信息 RU4X#gP4Vh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <>9!oOa
11、说明:四表联查问题: 1u7D:h>#
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 ..... ?YS>_MN
12、说明:日程安排提前五分钟提醒 pKy4***I3
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 6(d6Uwc`
13、说明:一条sql 语句搞定数据库分页 <A8>To<
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 6V]m0{:E
14、说明:前10条记录 :,aY|2si
select top 10 * form table1 where 范围 Sk>=C0f:
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.) !pw)sO~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Vi-Ph;6[
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 f+uyO7
(select a from tableA ) except (select a from tableB) except (select a from tableC) +"<+JRI(M5
17、说明:随机取出10条数据 *0^~@U
select top 10 * from tablename order by newid() F[Mwd &P@
18、说明:随机选择记录 fxPg"R!1i
select newid() gAdqZJR%]
19、说明:删除重复记录 :M6v<Kg{;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) yT_W\"=8
20、说明:列出数据库里所有的表名 `}#rcDK
select name from sysobjects where type='U' lMGO4U[z
21、说明:列出表里的所有的 m
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select name from syscolumns where id=object_id('TableName') !Z:XSF[T
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。 ^wd@mWxx
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 mXp#6'a
显示结果: X'PZCg W
type vender pcs S
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电脑 A 1 d7vPZ_j^z
电脑 A 1 s{' Sl{-Eu
光盘 B 2 `hj,rF+4
光盘 A 2 yj&GJuNb~
手机 B 3 s<F*kLib
手机 C 3 gPMfn:a-8
23、说明:初始化表table1 D/."0 #q
TRUNCATE TABLE table1 "x=\mA#`
24、说明:选择从10到15的记录 lEFd^@t
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0<\|D^m=&h
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三、技巧 js81@WX!c
1、1=1,1=2的使用,在SQL语句组合时用的较多 kx;X:I(5&P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, -/JEKwc
如: <3B^5p\/
if @strWhere !='' 80@\e
begin z.cDbkf}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [Xu8~c X
end gE2(E0H
else dRJ
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begin H:~p5t
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :.*Q@X}-I
end a|u#w~
我们可以直接写成 N# }w1]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere A?lLK&*
2、收缩数据库 3$!QP
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--重建索引 `}),wBq
DBCC REINDEX ..8t1+S6]
DBCC INDEXDEFRAG ]jhi"BM
--收缩数据和日志 ':4<[Vk
DBCC SHRINKDB Ep;uz5 ^8
DBCC SHRINKFILE uQO5GDuK>
3、压缩数据库 U7x
dbcc shrinkdatabase(dbname) 1 7~Pc
4、转移数据库给新用户以已存在用户权限 0vqH-)}
exec sp_change_users_login 'update_one','newname','oldname' 'r!!W0-K
go e` 4mrBtz|
5、检查备份集 S5hc@^|0Z
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' }h;Z_XF&
6、修复数据库 5<(*
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ALTER DATABASE [dvbbs] SET SINGLE_USER %>*?uO`z[
GO A5Jadz~
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $l7}e=1
GO uBww
ALTER DATABASE [dvbbs] SET MULTI_USER :5~Dca_iU4
GO <9pI~\@w
7、日志清除 PL=v,NB
SET NOCOUNT ON $=plAi
DECLARE @LogicalFileName sysname, j>JBZ#g
@MaxMinutes INT, i
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@NewSize INT rB+ (
USE tablename -- 要操作的数据库名 pA .orx
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 q<E7qY+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. KcV"<9rE
@NewSize = 1 -- 你想设定的日志文件的大小(M) {Ycgq%1>]
-- Setup / initialize YeOn
DECLARE @OriginalSize int ]#M"|iTR
SELECT @OriginalSize = size _W(xO
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FROM sysfiles $HQ~I?r{Hf
WHERE name = @LogicalFileName N#M>2b<A/T
SELECT 'Original Size of ' + db_name() + ' LOG is ' + TYuP
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + c(hC'Cp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7{U[cG+a#
FROM sysfiles ]xvhUv!G
WHERE name = @LogicalFileName ;*qXjv&
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CREATE TABLE DummyTrans w-WAgAch
(DummyColumn char (8000) not null) dwB#k$VIOw
DECLARE @Counter INT, =&pR=vl
@StartTime DATETIME, )b nGZ8h99
@TruncLog VARCHAR(255) lJAzG,f
SELECT @StartTime = GETDATE(), &H# l*
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' pu MVvo
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \&vXp"-@
EXEC (@TruncLog) eW.qMx#:od
-- Wrap the log if necessary. S3x^#83
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9*iVv)jd
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) bzpi7LKN
AND (@OriginalSize * 8 /1024) > @NewSize ,Z|O y|+'
BEGIN -- Outer loop. %pg)*>P h
SELECT @Counter = 0 ;,Vdj[W$>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1<x5{/CZ
BEGIN -- update oa+'.b~
INSERT DummyTrans VALUES ('Fill Log') =KR^0<2r
DELETE DummyTrans 0e>?!Z
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SELECT @Counter = @Counter + 1 R5MN;xG^
END uu4!e{K
EXEC (@TruncLog) <2j$P Y9
END n)cc\JPQ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,%m~OB#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + q:>`|~MX
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q@1A2L\Om
FROM sysfiles U'b}%[
WHERE name = @LogicalFileName iU0jv7}n
DROP TABLE DummyTrans SN[yC
SET NOCOUNT OFF hQ%X0X,
8、说明:更改某个表 U#Kw+slM
exec sp_changeobjectowner 'tablename','dbo' n}%_H4t
9、存储更改全部表 #\F8(lZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~>]Ie~E: (
@OldOwner as NVARCHAR(128), 6UN{Vjr%`
@NewOwner as NVARCHAR(128) qYqd -R
AS y54RD/`-
DECLARE @Name as NVARCHAR(128) /;TD n>lq
DECLARE @Owner as NVARCHAR(128) ^l(,'>Cn
DECLARE @OwnerName as NVARCHAR(128) !`U #Pjp.
DECLARE curObject CURSOR FOR S-6i5H"B&
select 'Name' = name, DS|x*w'I
'Owner' = user_name(uid) muK)Yw[#N
from sysobjects D_f:D^
where user_name(uid)=@OldOwner ,^iT,MgNNf
order by name '+|uv7|+v
OPEN curObject "H=fWz5z
FETCH NEXT FROM curObject INTO @Name, @Owner UA0R)BH'
WHILE(@@FETCH_STATUS=0) !vr
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BEGIN a<pEVV\NB~
if @Owner=@OldOwner u7wZPIC{_
begin &6Wim<*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) "g!/^A!!
exec sp_changeobjectowner @OwnerName, @NewOwner '~6l
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end FP6JfI8
-- select @name,@NewOwner,@OldOwner Q|Pm8{8
FETCH NEXT FROM curObject INTO @Name, @Owner C5^N)-]"
END K8iQ?
close curObject K!88 Nox(
deallocate curObject H#`&!p
GO B<!wh
10、SQL SERVER中直接循环写入数据 #b=*hi`E
declare @i int 0pe*DbYP5
set @i=1 4,6?sTuX
while @i<30 ~;uW)
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begin R<>uCF0
insert into test (userid) values(@i) Yceex}X*5
set @i=@i+1 -uK@2}NZ
end Eid~4a
小记存储过程中经常用到的本周,本月,本年函数 =~j S
Dateadd(wk,datediff(wk,0,getdate()),-1) QTI^?@+N>
Dateadd(wk,datediff(wk,0,getdate()),6) Bk4|ik}
Dateadd(mm,datediff(mm,0,getdate()),0) y{qKb:~wv
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 'P >h2^z
Dateadd(yy,datediff(yy,0,getdate()),0) $-]PD`wmY
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) n3kYVAgF
上面的SQL代码只是一个时间段 "sf]I[a
Dateadd(wk,datediff(wk,0,getdate()),-1) #Mz N7
Dateadd(wk,datediff(wk,0,getdate()),6) "K8<X
就是表示本周时间段. /#M|V6n
下面的SQL的条件部分,就是查询时间段在本周范围内的: xv{iWJcs
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) G*|2qX"o
而在存储过程中 huau(s0um
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) v*nX
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @"m?
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