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。 .vQ2w
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一、基础 e
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1、说明:创建数据库 Gjy'30IF
CREATE DATABASE database-name Duptles
2、说明:删除数据库 'O\K Wj{
drop database dbname Dvd.Q/f
3、说明:备份sql server ^Po\:x%o
--- 创建 备份数据的 device (nBJ,v)
USE master IeN!nK-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?_<ZCH
--- 开始 备份 :Oq!.uO
BACKUP DATABASE pubs TO testBack B TcxBh
4、说明:创建新表 ~&B_ Bswf
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) j nI)n*
根据已有的表创建新表: rQisk8%
A:create table tab_new like tab_old (使用旧表创建新表) '|Q=J)
B:create table tab_new as select col1,col2... from tab_old definition only dUjdQ
5、说明:删除新表 e5`{*g$i).
drop table tabname A.WJ#1i}E
6、说明:增加一个列 cO(|>&tJ
Alter table tabname add column col type J=4S\0Z*
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 f+<-Jc
7、说明:添加主键: Alter table tabname add primary key(col) 1RRvNZW
说明:删除主键: Alter table tabname drop primary key(col) )}WG`
8、说明:创建索引:create [unique] index idxname on tabname(col....) wy) Frg
删除索引:drop index idxname %HYC-TF#
注:索引是不可更改的,想更改必须删除重新建。 m}
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9、说明:创建视图:create view viewname as select statement u{6*}6@fi
删除视图:drop view viewname OY"{XnPZ
10、说明:几个简单的基本的sql语句 hC6$>tl
选择:select * from table1 where 范围 )%,bog(x
插入:insert into table1(field1,field2) values(value1,value2) )%ja6Vg
删除:delete from table1 where 范围 jgEiemh&
更新:update table1 set field1=value1 where 范围 [FyE{NfiJ%
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Z8'uZ#=Yw
排序:select * from table1 order by field1,field2 [desc] m"U\;Mw?
总数:select count as totalcount from table1 S'3l<sY
求和:select sum(field1) as sumvalue from table1 /-BplU*"9
平均:select avg(field1) as avgvalue from table1 |_O; U=2
最大:select max(field1) as maxvalue from table1 1/le%}mK
最小:select min(field1) as minvalue from table1 HCHC~FNd
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11、说明:几个高级查询运算词 yRieGf1'SD
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A: UNION 运算符 ;Rwr5
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。 Z71"d"
B: EXCEPT 运算符 yRvq3>mU
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。 OSkZW
C: INTERSECT 运算符 sBRw#xyS
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。 Q`19YX
注:使用运算词的几个查询结果行必须是一致的。 eKStt|M'
12、说明:使用外连接 NaVZ)
A、left outer join: L}:u9$w
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Yj0Ss{Ep
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H3a}`3}U
B:right outer join: {Ja#pt
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 aNXu"US+Sp
C:full outer join: %X[|7D-
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 (V e[FhA
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二、提升 vV=$N"bT~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 7Bmt^J5i&t
法一:select * into b from a where 1<>1 C'5i>;
法二:select top 0 * into b from a :Z=A,G
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) MWhFNfS8=
insert into b(a, b, c) select d,e,f from b; IL>Gi`Y&
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) r ."Dc
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ~@sx}u
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +Do7rl
4、说明:子查询(表名1:a 表名2:b) 26\1tOj Np
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) z
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5、说明:显示文章、提交人和最后回复时间 Y%wF;I1x
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Uyi_B.:`
6、说明:外连接查询(表名1:a 表名2:b) =cRJtn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c M:C*?;K:
7、说明:在线视图查询(表名1:a ) KZDB \T
select * from (SELECT a,b,c FROM a) T where t.a > 1; [
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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 -4hX-
select * from table1 where time between time1 and time2 &1B)mj
select a,b,c, from table1 where a not between 数值1 and 数值2 ]@WJ&e/'@
9、说明:in 的使用方法 :5"|iRP'
select * from table1 where a [not] in ('值1','值2','值4','值6') im1]:kr7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 I{1w8m4O6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #j; &g1
11、说明:四表联查问题: |0-5-.
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 ..... &:{|nDT_2
12、说明:日程安排提前五分钟提醒 M%B]f2C
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {}lw%d?A
13、说明:一条sql 语句搞定数据库分页 YTYYb#"Q
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 7i/?+|
14、说明:前10条记录 \=83#*KK
select top 10 * form table1 where 范围 =2`s Uw}
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.) YjG0: 9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) l<qxr.X
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 ]p#Zdm1EL
(select a from tableA ) except (select a from tableB) except (select a from tableC) KN+*_L-
17、说明:随机取出10条数据 TXy*- <#vR
select top 10 * from tablename order by newid() }-8K*A3
18、说明:随机选择记录 XPX{c|]>.
select newid() q:nYUW o
19、说明:删除重复记录 ]vu'+F$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Lw!@[;2
20、说明:列出数据库里所有的表名 1>|p1YZ"
select name from sysobjects where type='U' ,P9B8oIq
21、说明:列出表里的所有的 !})+WSs'"s
select name from syscolumns where id=object_id('TableName') GH:Au
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。 dd$\Q
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 [ ra[~
显示结果: x{ZcF=4
type vender pcs |t.WPp5,
电脑 A 1 u2U@Qrs2
电脑 A 1 f Z \Ev%F
光盘 B 2 fT'A{&h|U
光盘 A 2 uYO?Rb&}
手机 B 3 7 H<_
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手机 C 3 cJH7zumM)
23、说明:初始化表table1 (cA=~Bw[=
TRUNCATE TABLE table1 w@oq.K
24、说明:选择从10到15的记录 VDQ&BmJE
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc -G*u2i_*
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三、技巧 =#>P!
1、1=1,1=2的使用,在SQL语句组合时用的较多 qLPI^g,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, l kl#AH
如: ,cbP yg
if @strWhere !='' 1lx\Pz@ol
begin _
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere l sUQ7%f
end 1 bv L
else {O!fV<Vx 9
begin Cf%)W:Q9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' oXz:zoNQ
end =zbrXtp,
我们可以直接写成 7f
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere U(i2j)|^I3
2、收缩数据库 9N
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--重建索引 $v>- @
DBCC REINDEX g[Yok`e[
DBCC INDEXDEFRAG geT<vh Z6
--收缩数据和日志 vguqk!eo4
DBCC SHRINKDB |r3eq4$Am
DBCC SHRINKFILE Wc+ e>*
3、压缩数据库 r5F#q
dbcc shrinkdatabase(dbname) y6G[-?"/Q
4、转移数据库给新用户以已存在用户权限 <Ojf&C^Z
exec sp_change_users_login 'update_one','newname','oldname' =8<SKY&\X
go j[=f;&1
5、检查备份集 "w|GIjE+
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .>H7i`1D`
6、修复数据库 4$y|z{[<
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ALTER DATABASE [dvbbs] SET SINGLE_USER 4\-kzGgmo
GO `%rqQnVB
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK a:P%
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GO C0kwI*)
ALTER DATABASE [dvbbs] SET MULTI_USER cIq3En
GO =P2T&Gb
7、日志清除 x#pTB.
SET NOCOUNT ON m4kmJaM
DECLARE @LogicalFileName sysname, _u.l|yR
@MaxMinutes INT, cL`l1:j\}
@NewSize INT \)LY_D:
USE tablename -- 要操作的数据库名 iaPY>EP1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #>!!#e!*
@MaxMinutes = 10, -- Limit on time allowed to wrap log. EV~_-YC
@NewSize = 1 -- 你想设定的日志文件的大小(M) WlG/7$
-- Setup / initialize Zb}=?fcL;@
DECLARE @OriginalSize int ~omX(kPzK
SELECT @OriginalSize = size ^yBx.GrQc
FROM sysfiles R=PjLH&)
WHERE name = @LogicalFileName i%-c/ lop
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Q@l3XNH|c
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^>]p4Q3 6
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' bD49$N?>
FROM sysfiles u6|7P<HUfb
WHERE name = @LogicalFileName "esV#%:#J
CREATE TABLE DummyTrans iUSs) []H>
(DummyColumn char (8000) not null) f$/Daq <M
DECLARE @Counter INT, <v0 d8
@StartTime DATETIME, :a`l_RMU
@TruncLog VARCHAR(255) YMm Fpy
SELECT @StartTime = GETDATE(), =FdS'<GM
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S* <:He&1
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /A{znE
EXEC (@TruncLog) bC"#.e
-- Wrap the log if necessary. u QCQ$
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;:'A{&0N
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) $L;7SY?
AND (@OriginalSize * 8 /1024) > @NewSize 5w{_WR6,
BEGIN -- Outer loop. 9I.="b=J)
SELECT @Counter = 0 {OB\~$TH
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6B|IbQ^
BEGIN -- update wn|Sdp
INSERT DummyTrans VALUES ('Fill Log') , gz:2UY#
DELETE DummyTrans Rrk3EL
SELECT @Counter = @Counter + 1 uv._N6mj
END xNl_Q8Z?R^
EXEC (@TruncLog) UJlKw `4
END %hOe `2#$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6kYn5:BhIi
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _%"/I96'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -CxaOZG
FROM sysfiles )<jj O
WHERE name = @LogicalFileName 7FfzMs[\e
DROP TABLE DummyTrans /z~;.jRg
SET NOCOUNT OFF Tpkm\_
8、说明:更改某个表 OSsdB%bIu`
exec sp_changeobjectowner 'tablename','dbo' Q- j+#NGc
9、存储更改全部表 P>jlFm
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "TG}aS
@OldOwner as NVARCHAR(128), ar>S_VW*
@NewOwner as NVARCHAR(128) kM@8RAxA
AS 8'/vW ~f
DECLARE @Name as NVARCHAR(128) 7pr@aA"vgj
DECLARE @Owner as NVARCHAR(128) * 496"kU
DECLARE @OwnerName as NVARCHAR(128) lts{<AU~
DECLARE curObject CURSOR FOR J
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select 'Name' = name, >5)$Qtz#
'Owner' = user_name(uid) aq[kKS`
from sysobjects I?5#Q0,b
where user_name(uid)=@OldOwner X[|-F3o
order by name eX$u
OPEN curObject 42X[Huy]
FETCH NEXT FROM curObject INTO @Name, @Owner 2z&HT SI
WHILE(@@FETCH_STATUS=0) QnVYZUgJeV
BEGIN \vojF\
if @Owner=@OldOwner /R@eOl}D
begin &o:wSe
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6uR:/PTG
exec sp_changeobjectowner @OwnerName, @NewOwner bi[vs|
end JZ80 |-c
-- select @name,@NewOwner,@OldOwner ?v `0KF
FETCH NEXT FROM curObject INTO @Name, @Owner [
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END lYD-U8
close curObject LB U]^t@ M
deallocate curObject dsrzXmE0
GO ANi}q9SC
10、SQL SERVER中直接循环写入数据 qp'HRh@P2:
declare @i int 'tp+g3V
set @i=1 s#-`,jqD
while @i<30 57D /"
begin -hyY5!rD
insert into test (userid) values(@i) M~p=OM<
set @i=@i+1 _Su$oOy(Ea
end 8^^Xr
小记存储过程中经常用到的本周,本月,本年函数 4GeWo@8h
Dateadd(wk,datediff(wk,0,getdate()),-1) w}YO+
Dateadd(wk,datediff(wk,0,getdate()),6) x4R[Q&:M
Dateadd(mm,datediff(mm,0,getdate()),0) U
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) )Q&:$]
Dateadd(yy,datediff(yy,0,getdate()),0) y kwS-e
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1Ep!U#Del
上面的SQL代码只是一个时间段 U''/y\Z
Dateadd(wk,datediff(wk,0,getdate()),-1) x>Q\j>^
Dateadd(wk,datediff(wk,0,getdate()),6) -05#/-Z=
就是表示本周时间段. >>F E?@
下面的SQL的条件部分,就是查询时间段在本周范围内的: 9;sebqC?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $hn#T#J3
而在存储过程中 4*G#fW-
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Mp}aJzmkB;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ixp(^>ZN