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。 u1t%(_h
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一、基础 =g/{%;
1、说明:创建数据库 kHXL8k#T
CREATE DATABASE database-name XD |E=s
2、说明:删除数据库 ^[]}R:
drop database dbname )p
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3、说明:备份sql server "J+3w
--- 创建 备份数据的 device ~2<7ZtV=
USE master ]d,S749(s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' >2~+.WePu
--- 开始 备份 350_CN,
BACKUP DATABASE pubs TO testBack .%.9n\b
4、说明:创建新表 ,stN
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +6UVn\9Q
根据已有的表创建新表: m<{<s T
A:create table tab_new like tab_old (使用旧表创建新表) .jS~By|r
B:create table tab_new as select col1,col2... from tab_old definition only $rz=6h
5、说明:删除新表 ^\\Tx*#i
drop table tabname GKvN*
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6、说明:增加一个列 @kk4]:,w
Alter table tabname add column col type _u{c4U0,
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。 VUVaaOmO
7、说明:添加主键: Alter table tabname add primary key(col) P8^hBv*
说明:删除主键: Alter table tabname drop primary key(col) { T4
8、说明:创建索引:create [unique] index idxname on tabname(col....) `VKf3&|<A
删除索引:drop index idxname A]YVs
注:索引是不可更改的,想更改必须删除重新建。 \]P!.}nX#
9、说明:创建视图:create view viewname as select statement gN24M3{C
删除视图:drop view viewname '3TW [!m
10、说明:几个简单的基本的sql语句 f@8>HCI
选择:select * from table1 where 范围 dY@WI[yog
插入:insert into table1(field1,field2) values(value1,value2) a["2VY6Eq@
删除:delete from table1 where 范围 vJ\pR~?
更新:update table1 set field1=value1 where 范围 N` aF{3[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 43={Xy
排序:select * from table1 order by field1,field2 [desc] T^T[$26
总数:select count as totalcount from table1 r) $+
求和:select sum(field1) as sumvalue from table1 *NkA8PC
平均:select avg(field1) as avgvalue from table1 'rMN=1:iu"
最大:select max(field1) as maxvalue from table1 [|P!{?A43|
最小:select min(field1) as minvalue from table1 A;/-u<f
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11、说明:几个高级查询运算词 \"CZI<=TB
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A: UNION 运算符 wNQ*t-K
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 }b=}uiR#
B: EXCEPT 运算符 :T]o)
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 si&S%4(
C: INTERSECT 运算符 f 1w~!O9
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。
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注:使用运算词的几个查询结果行必须是一致的。 dDm):Z*`b
12、说明:使用外连接 )\6&12rj
A、left outer join: 66.5QD0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 0j30LXI_
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c vhsk0$f
B:right outer join: qw@puw@D
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。 .pfP7weQ
C:full outer join: 2zVJ vn7
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。 1AG=%F|.
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二、提升 Kv.>Vf.T}_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .so[I
法一:select * into b from a where 1<>1 q4}PM[K?=\
法二:select top 0 * into b from a \e!vj.PU
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) fO0(Z
insert into b(a, b, c) select d,e,f from b; OfctoPP _0
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) "I=\[l8t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 t5'V6nv
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Nluv/?<
4、说明:子查询(表名1:a 表名2:b) pGf@z:^{*-
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) {e+-vl
5、说明:显示文章、提交人和最后回复时间 ?[)}l9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;]gP@ h/
6、说明:外连接查询(表名1:a 表名2:b) <$ F\Nk|x
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c yY[<0|o u
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; taFn![}/!g
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 87:!C5e}
select * from table1 where time between time1 and time2 5aln>1x>hn
select a,b,c, from table1 where a not between 数值1 and 数值2 tZ `z
9、说明:in 的使用方法 X{we/'>
select * from table1 where a [not] in ('值1','值2','值4','值6') mp9{m`Jb*
10、说明:两张关联表,删除主表中已经在副表中没有的信息 G:pEE:W[
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) U$
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11、说明:四表联查问题: '@jXbN
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 ..... jM$`(Y
12、说明:日程安排提前五分钟提醒 3GuH857ov
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4O;OjUI0a
13、说明:一条sql 语句搞定数据库分页 _~rI+l A
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 zo[[>MA
14、说明:前10条记录 ^|/](
select top 10 * form table1 where 范围 W?eu!wL#p
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.) } ~"hC3w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0pJ
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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 ZTU&,1Y ;
(select a from tableA ) except (select a from tableB) except (select a from tableC) "y_#7K
17、说明:随机取出10条数据 A |3tI
select top 10 * from tablename order by newid() G7)Fk%>
18、说明:随机选择记录 p=C%Hmd5E
select newid() m;D- u>o
19、说明:删除重复记录 Wm);C~Le
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) $KLD2BAL
20、说明:列出数据库里所有的表名 I! > \#K
select name from sysobjects where type='U' 05snuNt]-
21、说明:列出表里的所有的 iJZ/jCI
select name from syscolumns where id=object_id('TableName') e|&6$A>4]
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。 /F4pb]U!*
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 81hbk((
显示结果: .\8X[%K9nc
type vender pcs y_HN6
电脑 A 1 T"&)&"W*U
电脑 A 1 FL8g5I
光盘 B 2 - !>}_AH
光盘 A 2 OvUI@,Ef
手机 B 3 'yV?*a
手机 C 3 b8%C*r7
23、说明:初始化表table1 WBN w~|DO]
TRUNCATE TABLE table1 +&Hr4@pgW
24、说明:选择从10到15的记录 \EKU*5\Hp>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Zum0J{l
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三、技巧 _:X|.W
1、1=1,1=2的使用,在SQL语句组合时用的较多 p|Q*5TO
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !<UJ6t}
如: 7C$
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if @strWhere !='' ZkIgL
begin +8v9flh
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere = <j"M85.
end N gLU$/y;
else _=q!
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begin [tg^GOf '
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' H)aQ3T4N5
end etoo
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我们可以直接写成 Qb!PRCHQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere N<QjdD&
2、收缩数据库 hzI|A~MFB
--重建索引 A<6%r7&B'
DBCC REINDEX q~@]W=
DBCC INDEXDEFRAG eeHP&1= 7
--收缩数据和日志 6<'rG''
DBCC SHRINKDB "Tm[t?FMbe
DBCC SHRINKFILE ,^gyH
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3、压缩数据库 R |f~>JUF
dbcc shrinkdatabase(dbname) qim
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4、转移数据库给新用户以已存在用户权限 7T"XPV|W6
exec sp_change_users_login 'update_one','newname','oldname' rU;RGz6}
go r1<F
5、检查备份集 avy"r$v_&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ja SI^go
6、修复数据库 Ug:\
ALTER DATABASE [dvbbs] SET SINGLE_USER Qj3a_p$)P
GO ,ZQZ}`x(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <BO)E(
GO !r`, =jK"
ALTER DATABASE [dvbbs] SET MULTI_USER 1Nu1BLPm
GO uZZU{U9h
7、日志清除 7},)]da>,'
SET NOCOUNT ON \`ZW* EtPI
DECLARE @LogicalFileName sysname, ]r3Kg12Mi
@MaxMinutes INT, S}f?.7
@NewSize INT =CL}
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USE tablename -- 要操作的数据库名 1yV: qp
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 h?-#9<A
@MaxMinutes = 10, -- Limit on time allowed to wrap log. I+ es8
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,+g&o^T
-- Setup / initialize f50L,4,
DECLARE @OriginalSize int $!5\E>y#
SELECT @OriginalSize = size bWZbG{Y.
FROM sysfiles VyRsPg[(
WHERE name = @LogicalFileName v4RlLgdS%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + x+]!m/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + XX1Il;1G#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Iyd?|f"
FROM sysfiles T~fmk
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WHERE name = @LogicalFileName %+ FG ,d
CREATE TABLE DummyTrans [ >^PRs
(DummyColumn char (8000) not null) ,-+"^>
DECLARE @Counter INT, j
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@StartTime DATETIME, X[2[!)Rk
@TruncLog VARCHAR(255) cpt<WK}
SELECT @StartTime = GETDATE(), 6{,HiY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' En&5)c+js4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) k'$!(*]\b
EXEC (@TruncLog) bln/1iS
-- Wrap the log if necessary. q~L^au8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired s/:Fwr4q#a
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p'sc0@}_O
AND (@OriginalSize * 8 /1024) > @NewSize @$"L:1_
BEGIN -- Outer loop. )HD`O~M>
SELECT @Counter = 0 `:O\dN>ON
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) J(#mtj>v_
BEGIN -- update JbO ~n
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INSERT DummyTrans VALUES ('Fill Log') ]#/4Y_d
DELETE DummyTrans }tPk@$
SELECT @Counter = @Counter + 1 m^_6:Q0F!8
END ~^^ NHq
EXEC (@TruncLog) .)|a2d ~F
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + -
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + O)kgBrB
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Y~)T
FROM sysfiles h;V,n
WHERE name = @LogicalFileName Z+pom7A"E
DROP TABLE DummyTrans E42eOGp9i
SET NOCOUNT OFF ]APvp.Tw:
8、说明:更改某个表 dr{y0`CCN
exec sp_changeobjectowner 'tablename','dbo' YpUp@/"
9、存储更改全部表 "4H8A=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5efxEt>U
@OldOwner as NVARCHAR(128), g(O;{Q_
@NewOwner as NVARCHAR(128) ;WT{|z
AS -Q;#sJ?
DECLARE @Name as NVARCHAR(128) vG^#Sfgtw
DECLARE @Owner as NVARCHAR(128) hF3&i=;.
DECLARE @OwnerName as NVARCHAR(128) AM} brO
DECLARE curObject CURSOR FOR (-NHxo
select 'Name' = name, *2}O-e
'Owner' = user_name(uid) k>E`s<3
from sysobjects |3K)$.6~
where user_name(uid)=@OldOwner 1! p/6
order by name yMLOUUWa8x
OPEN curObject 'SLE;_TD
FETCH NEXT FROM curObject INTO @Name, @Owner o5\b'hR*#
WHILE(@@FETCH_STATUS=0) n:U>Fj>q
BEGIN VGw(6`|!
if @Owner=@OldOwner :)jJge&^p
begin ;Qi }{;+
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~#}Dx
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exec sp_changeobjectowner @OwnerName, @NewOwner 9kKnAf4Z
end D\^WXY5e%y
-- select @name,@NewOwner,@OldOwner xjdw'v+qZo
FETCH NEXT FROM curObject INTO @Name, @Owner 2JmZ{
END w:o-klKXY
close curObject iRG?# "
deallocate curObject Je4Z(kj 0
GO ^*R(!P^
10、SQL SERVER中直接循环写入数据 rVQX7l# YI
declare @i int rOD1_X-
set @i=1 {dPgf
while @i<30 oK+
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begin %lr|xX
insert into test (userid) values(@i) 'f/Lv@]a
set @i=@i+1 jnuY{0(&
end [ neXFp}S
小记存储过程中经常用到的本周,本月,本年函数 R.j1?\
Dateadd(wk,datediff(wk,0,getdate()),-1) |m,VTViv;i
Dateadd(wk,datediff(wk,0,getdate()),6) OlxX.wP
Dateadd(mm,datediff(mm,0,getdate()),0) Q\{x)|{$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) [O-sVYB
Dateadd(yy,datediff(yy,0,getdate()),0) >+cVs:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ,/&Zw01dGN
上面的SQL代码只是一个时间段 %u p}p/?
Dateadd(wk,datediff(wk,0,getdate()),-1) 2
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Dateadd(wk,datediff(wk,0,getdate()),6) h5|.Et
就是表示本周时间段. H L<s@kEZ
下面的SQL的条件部分,就是查询时间段在本周范围内的: tn/T6C^)
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <XQ.A3SG!
而在存储过程中 HTz+K6&
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) c\cZ]RZ
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) MM{_Ur7Q