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。 @L>q(Kg
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一、基础 ^w(p8G_-w
1、说明:创建数据库 s<*XNNE7
CREATE DATABASE database-name 0F@"b{&0
2、说明:删除数据库 7]^M>#
drop database dbname (>F%UY
3、说明:备份sql server pR
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--- 创建 备份数据的 device 6Ca(U'
USE master _= +V/=
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ,pqGX3
--- 开始 备份 `%CtWJ(e
BACKUP DATABASE pubs TO testBack J+[_Wd
4、说明:创建新表 "nZ*{uv
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #@^t;)|
根据已有的表创建新表: Q&MZN);.
A:create table tab_new like tab_old (使用旧表创建新表) 0*%Z's\M"
B:create table tab_new as select col1,col2... from tab_old definition only qi;f^9M%
5、说明:删除新表 OH;b"]
drop table tabname
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6、说明:增加一个列 k:*S&$S!E
Alter table tabname add column col type dArDP[w
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 'I_Qb$
7、说明:添加主键: Alter table tabname add primary key(col) 0zo?eI
说明:删除主键: Alter table tabname drop primary key(col) 9dFy"yxYa
8、说明:创建索引:create [unique] index idxname on tabname(col....) e&7JpT
删除索引:drop index idxname /[O(ea$U
注:索引是不可更改的,想更改必须删除重新建。 K|Ld,bq
9、说明:创建视图:create view viewname as select statement JmPHAUd
删除视图:drop view viewname W)9K`hM6
10、说明:几个简单的基本的sql语句 ] x\-$~E
选择:select * from table1 where 范围 eK.e|z|
插入:insert into table1(field1,field2) values(value1,value2) j2Tr$gx<
删除:delete from table1 where 范围 >"gf3rioW
更新:update table1 set field1=value1 where 范围 r~N"ere26
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )A!>=2M`
排序:select * from table1 order by field1,field2 [desc] (EK"V';
总数:select count as totalcount from table1 EG0WoUX|
求和:select sum(field1) as sumvalue from table1 u1t%(_h
平均:select avg(field1) as avgvalue from table1 $SM#< @
最大:select max(field1) as maxvalue from table1 Ae69>bkE0
最小:select min(field1) as minvalue from table1 r;>*_Oc7g
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11、说明:几个高级查询运算词 =3q/F7-
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A: UNION 运算符 ;FBUwR}
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。 0|2%vh >J
B: EXCEPT 运算符 $wmvKQc{lx
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 bA=
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C: INTERSECT 运算符 (:._"jp]
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 SGh1 DB
注:使用运算词的几个查询结果行必须是一致的。 n3}!p'-CC
12、说明:使用外连接 *F
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A、left outer join: U"q/rcA
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Qi_>Mg`x
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c U Z.=aQ}M
B:right outer join: r)Ap8?+
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 V2$h8\a
C:full outer join: CLeG<Hi
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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。 b'J'F;zh>
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二、提升 Q>/C*@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )N=NR2xBZ
法一:select * into b from a where 1<>1 D<8HZ%o
法二:select top 0 * into b from a AK\$i$@6
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :>D[n1v
insert into b(a, b, c) select d,e,f from b; #[zI5)Meh
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ZZcEt
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (7XCA,KTGI
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. W5?yy>S6N
4、说明:子查询(表名1:a 表名2:b) V6t,BJjS
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) `kbSu}
5、说明:显示文章、提交人和最后回复时间 6T+FH;h
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 5O~HWBX.
6、说明:外连接查询(表名1:a 表名2:b) Mr?Xp(.}G
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ox:[f9.5
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; N-I5X2
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 :!5IW?2
select * from table1 where time between time1 and time2 5m?8yT}
select a,b,c, from table1 where a not between 数值1 and 数值2 8'<-:KG
9、说明:in 的使用方法 )t$,e2FY
select * from table1 where a [not] in ('值1','值2','值4','值6') w4W_iaU
10、说明:两张关联表,删除主表中已经在副表中没有的信息 +<xQM h8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }Z{=|rVE
11、说明:四表联查问题: LEW'G"+
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 ..... *g y{]
12、说明:日程安排提前五分钟提醒 $ "E).j
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0G7K8`a
13、说明:一条sql 语句搞定数据库分页 >=UF-xk;
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 w=LP"bqlI
14、说明:前10条记录 c6nflk.l
select top 10 * form table1 where 范围 A,\6nO67
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.) ?CC"Yij
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2 Yp7
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 {]E+~%Va
(select a from tableA ) except (select a from tableB) except (select a from tableC) e&>;*$)
17、说明:随机取出10条数据 h3*Zfl<]
select top 10 * from tablename order by newid() 3pK*~VK
18、说明:随机选择记录 L:_bg8eD#
select newid() LbaK={tR
19、说明:删除重复记录 @;<ht c
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) jV?
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20、说明:列出数据库里所有的表名 PQK(0iCo4
select name from sysobjects where type='U' ?T>'j mmV=
21、说明:列出表里的所有的 z;A>9vQ_J
select name from syscolumns where id=object_id('TableName') R,9[hNHWGs
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。 Row)hx8
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 3 n'V\Hvz
显示结果: L]d-hs
type vender pcs Hir Fl
电脑 A 1 D8>enum
电脑 A 1 /e]'u&a
光盘 B 2 TjQvAkT
光盘 A 2 vC1v"L;[o/
手机 B 3 YnxRg
手机 C 3 n|b5? 3
23、说明:初始化表table1 $/=nU*pd
TRUNCATE TABLE table1 L=q+|j1>
24、说明:选择从10到15的记录 p98~&\QT
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4hAl-8~Q6
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三、技巧 .&9 i
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]8T |f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, FXzFHU/dP
如: :6zG7qES3
if @strWhere !='' H ,+?
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begin xdf82)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =JKv:</.G
end mt5KbA>nU
else cs1l~bl
begin 6ezS {Q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l5g$vh\aQ]
end 1j:Wh
我们可以直接写成 d'/TdVM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere J|X
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2、收缩数据库 F
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--重建索引 ;Ra+=z}>
DBCC REINDEX Pb8^ b
DBCC INDEXDEFRAG $<^u^q37u
--收缩数据和日志 "Kc>dJ@W
DBCC SHRINKDB wMdal:n^
DBCC SHRINKFILE GrTulN?
3、压缩数据库 6I!7c^]t
dbcc shrinkdatabase(dbname) :=8t"rO=W
4、转移数据库给新用户以已存在用户权限 c%[#~;E
exec sp_change_users_login 'update_one','newname','oldname' KN?6;G{
go ithewup
5、检查备份集 LwhyE:1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' /F4pb]U!*
6、修复数据库 81hbk((
ALTER DATABASE [dvbbs] SET SINGLE_USER [74F6Qp
GO H(Q.a=&4!p
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w.lAQ5)I%\
GO =xNv\e
ALTER DATABASE [dvbbs] SET MULTI_USER Q>R>R*1.j
GO F29va
7、日志清除 >~`r:0',
SET NOCOUNT ON {X*^s5{;H
DECLARE @LogicalFileName sysname, ;b`[&g
@MaxMinutes INT, K
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@NewSize INT ^':!1
USE tablename -- 要操作的数据库名 j:,NE(DF
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 )r[&RGz6
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !!4Qj
@NewSize = 1 -- 你想设定的日志文件的大小(M) V^hE}`>z&
-- Setup / initialize ZVbl88,(l
DECLARE @OriginalSize int n @?4b8"
SELECT @OriginalSize = size _:X|.W
FROM sysfiles t9Y=m6
WHERE name = @LogicalFileName P%#*-zCCx
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Vpr/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + KAsS[
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *1 G>YH
FROM sysfiles GEEW?8
WHERE name = @LogicalFileName uA$<\fnz
CREATE TABLE DummyTrans (u]N
(DummyColumn char (8000) not null) `u.t[
DECLARE @Counter INT, \~BDm
@StartTime DATETIME, f8SL3+v
@TruncLog VARCHAR(255) m$9w"8R
SELECT @StartTime = GETDATE(), f+|$&p%
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Qc[3Fq,f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 8E8N6
EXEC (@TruncLog) kN%MP6? J
-- Wrap the log if necessary. &AlJ "N|
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired A<6%r7&B'
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) q~@]W=
AND (@OriginalSize * 8 /1024) > @NewSize eeHP&1= 7
BEGIN -- Outer loop. S.Z9$k%
SELECT @Counter = 0 n.sbr
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) fM #7 y [
BEGIN -- update RN)dS>$
INSERT DummyTrans VALUES ('Fill Log') 3SSm5{197
DELETE DummyTrans MwfOy@|N
SELECT @Counter = @Counter + 1 '{[5M!B
END 5C"QE8R o
EXEC (@TruncLog) BW"&6t#kA
END ->h6j
SELECT 'Final Size of ' + db_name() + ' LOG is ' + `;YU.*
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + gtYAHi
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T \CCF
FROM sysfiles >Bs#Xb_B]
WHERE name = @LogicalFileName YPzU-:3
DROP TABLE DummyTrans ;SwMu@tg
SET NOCOUNT OFF DAwqo.m
8、说明:更改某个表 Yk42(!
exec sp_changeobjectowner 'tablename','dbo' ?x^z]N|P
9、存储更改全部表 ~V/?H!r'{}
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }gkM^*$:%
@OldOwner as NVARCHAR(128), 6G}+gqbX
@NewOwner as NVARCHAR(128) (_4;') 9
AS Ne$"g[uFU
DECLARE @Name as NVARCHAR(128) ?=VOD #)
DECLARE @Owner as NVARCHAR(128) UxD5eJJ
DECLARE @OwnerName as NVARCHAR(128) Kf 2jD4z}
DECLARE curObject CURSOR FOR q %0Cg=
select 'Name' = name, hky;CD~$
'Owner' = user_name(uid) O$kq`'9
from sysobjects peJKNX.!q
where user_name(uid)=@OldOwner
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order by name c*`>9mv
OPEN curObject .>wv\i[p
FETCH NEXT FROM curObject INTO @Name, @Owner =?h~.lo
WHILE(@@FETCH_STATUS=0) 0 a~HiIh
BEGIN ZhNdB
if @Owner=@OldOwner cpt<WK}
begin GabYfUkO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) En&5)c+js4
exec sp_changeobjectowner @OwnerName, @NewOwner k'$!(*]\b
end vA)O{W\o
-- select @name,@NewOwner,@OldOwner c8Q]!p+Yp
FETCH NEXT FROM curObject INTO @Name, @Owner cEe?*\G
END p#SY /KIw
close curObject U$H@ jJ*
deallocate curObject #q3l!3\mW
GO k z"3ZDR
10、SQL SERVER中直接循环写入数据 *WE1;msr
declare @i int 3x~{QG5Gn
set @i=1 _U{([M>;
while @i<30 #{9G sD
begin -o+74=E8[?
insert into test (userid) values(@i) =pA
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set @i=@i+1 F`nb21{0y&
end QQe;1O
小记存储过程中经常用到的本周,本月,本年函数 9s}Kl($
Dateadd(wk,datediff(wk,0,getdate()),-1) ](eN@Xi&@
Dateadd(wk,datediff(wk,0,getdate()),6) ^`SA'F,
Dateadd(mm,datediff(mm,0,getdate()),0) u*7Z~R
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kkvtB<<Y
Dateadd(yy,datediff(yy,0,getdate()),0) W$qd/'%
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) E42eOGp9i
上面的SQL代码只是一个时间段 @<M*qK1h
Dateadd(wk,datediff(wk,0,getdate()),-1) dr{y0`CCN
Dateadd(wk,datediff(wk,0,getdate()),6) -[OXSaf6
就是表示本周时间段. "4H8A=
下面的SQL的条件部分,就是查询时间段在本周范围内的: $|$e%
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) g(O;{Q_
而在存储过程中 ;WT{|z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -Q;#sJ?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) +>7$4`Nb2