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。 b xT|
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一、基础 -5~&A6+ILn
1、说明:创建数据库 D@5AI
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CREATE DATABASE database-name O*dN+o
2、说明:删除数据库 s6|EvIVM
drop database dbname 6ZCSCBW
3、说明:备份sql server PO,mg?JG(
--- 创建 备份数据的 device CE19V:zp
USE master +&7D
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' "r Bb2.
--- 开始 备份 XUrxnJ4
BACKUP DATABASE pubs TO testBack `c zL$tN<P
4、说明:创建新表 cZ{-h
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) M}]E,[
根据已有的表创建新表: 4#o Lf1
A:create table tab_new like tab_old (使用旧表创建新表) ppjS|l*`
B:create table tab_new as select col1,col2... from tab_old definition only *TEgV
5、说明:删除新表 n -P)X<\
drop table tabname #G;0yB:76
6、说明:增加一个列 M7|k"izv
Alter table tabname add column col type i1"4ztZ
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。 Vu3;U
7、说明:添加主键: Alter table tabname add primary key(col) 4PwjG;!K
说明:删除主键: Alter table tabname drop primary key(col) $y\\?
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^x8yWbrE
删除索引:drop index idxname tiI:yq0
注:索引是不可更改的,想更改必须删除重新建。 GS%ACk
9、说明:创建视图:create view viewname as select statement fZQC'Z>EX
删除视图:drop view viewname 38Q>x
10、说明:几个简单的基本的sql语句 F aOfe] F
选择:select * from table1 where 范围 |]tIE{d
插入:insert into table1(field1,field2) values(value1,value2) FOA y'76p
删除:delete from table1 where 范围 ?=X G#we
更新:update table1 set field1=value1 where 范围 XN@F6Gj
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! bi y1!r
排序:select * from table1 order by field1,field2 [desc] 6tC0F=
总数:select count as totalcount from table1 y6bl&_
求和:select sum(field1) as sumvalue from table1 /T53"+7:0
平均:select avg(field1) as avgvalue from table1 OaeGukhX&
最大:select max(field1) as maxvalue from table1 ]chfa
最小:select min(field1) as minvalue from table1 8cV3VapF
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11、说明:几个高级查询运算词 [ &cCE
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A: UNION 运算符 6 XZF8W
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。 nU{}R"|
B: EXCEPT 运算符 `*5_`^t
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。 /0PBY-O
C: INTERSECT 运算符 .d)X.cO
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。 21b
注:使用运算词的几个查询结果行必须是一致的。 K+=cNC4B
12、说明:使用外连接 vhA4ol
A、left outer join: 0}a="`p#<
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。 $IZ02ZM$
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 PyOj{WX>W
B:right outer join: E;Akm':
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。 zGfF.q}
C:full outer join: ^W&qTSjh
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。 R4 8w\?L
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二、提升 n]?KDID;
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'G6g
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法一:select * into b from a where 1<>1 ~C|. .Z
法二:select top 0 * into b from a S?ypka"L
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) '&XL|_Iq
insert into b(a, b, c) select d,e,f from b; w}wABO
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) }Zs
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 '<}N`PS#N
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. =0Z^q0.
4、说明:子查询(表名1:a 表名2:b) `Bw>0%.
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) T*AXS|=ju
5、说明:显示文章、提交人和最后回复时间
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (#uz_/xXa
6、说明:外连接查询(表名1:a 表名2:b) #le1
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c LHQ$0LVt>T
7、说明:在线视图查询(表名1:a ) !'y9/
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2pKkg>/S
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 :gD=F &V
select * from table1 where time between time1 and time2 rb"J{^
select a,b,c, from table1 where a not between 数值1 and 数值2 =;hz,+
9、说明:in 的使用方法 it
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select * from table1 where a [not] in ('值1','值2','值4','值6') (n4\$LdP-
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3`%]3qd}
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ljr?Z,R4
11、说明:四表联查问题: %25GplMT
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... )Z.v fc
12、说明:日程安排提前五分钟提醒 {5%u G2g
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8dgi"/[3
13、说明:一条sql 语句搞定数据库分页 FX"j8i/N
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 V7+fNr]I
14、说明:前10条记录 Rm^3K
select top 10 * form table1 where 范围 /2%646
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) UDBMf2F]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &7K 4tL
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 T?4pV#
(select a from tableA ) except (select a from tableB) except (select a from tableC) >-%tvrS%
17、说明:随机取出10条数据 /6K9? /
select top 10 * from tablename order by newid() 2=\} 0
18、说明:随机选择记录 Nk#[~$Q-1
select newid() (hB+DPi
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -2o_ L?
20、说明:列出数据库里所有的表名 5]-q.A5m
select name from sysobjects where type='U' ?@*hU2MTC
21、说明:列出表里的所有的 $(3mpQAg
select name from syscolumns where id=object_id('TableName') tsYBZaH
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 |^S{vub
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type aEL^N0\d
显示结果: `(2Y%L(r
type vender pcs CXI%8eFXe$
电脑 A 1 ]AB<OjF1c|
电脑 A 1 |\#~
光盘 B 2 jpGZ&L7i&
光盘 A 2 _Se0,Uns
手机 B 3 C\3;o]
手机 C 3 W(gOidKKz
23、说明:初始化表table1 >8v4fk
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TRUNCATE TABLE table1 yH9(ru
24、说明:选择从10到15的记录 ]!um}8!}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc sz"N,-<Ig
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三、技巧 D1ep7ykY
1、1=1,1=2的使用,在SQL语句组合时用的较多 y-.<iq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 5YZh e4R
如: _A>?@3La9
if @strWhere !='' k1.h |&JJN
begin )z".lw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %X5p\VS\7
end ;4MC/Q/
else ^MXW,xqb
begin HQy:,_f@
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' cF2!By3M
end ++gWyzD
我们可以直接写成 762c`aP_(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere _
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2、收缩数据库 TJO?BX_9
--重建索引 GJ9'i-\*\
DBCC REINDEX iAl.(j
DBCC INDEXDEFRAG j;7:aM"BQW
--收缩数据和日志 *^+]`S
DBCC SHRINKDB j5Cf\*B4J
DBCC SHRINKFILE hFQ*50n}
3、压缩数据库 ]B2%\}c
dbcc shrinkdatabase(dbname) k#oe:u`<
4、转移数据库给新用户以已存在用户权限 'PS_|zI
exec sp_change_users_login 'update_one','newname','oldname' p.ks
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go j*6>{_[
5、检查备份集 wni^qs.i@3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +lhjz*0
6、修复数据库 +~7x+6E
ALTER DATABASE [dvbbs] SET SINGLE_USER +I<^w)
GO "Dt:
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ns&3Dh(IVP
GO x@p1(V.
ALTER DATABASE [dvbbs] SET MULTI_USER S^ q%+Z
GO ?!Wh ^su-
7、日志清除 L!c.1Rf_
SET NOCOUNT ON \z8j6 h
DECLARE @LogicalFileName sysname, F*Y]^9]
@MaxMinutes INT, -T8'|"g
@NewSize INT CZzgPId%x
USE tablename -- 要操作的数据库名 3+4U?~^k*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 G'<Ie@$6l
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <1pRAN0
@NewSize = 1 -- 你想设定的日志文件的大小(M) ~p!=w#/
-- Setup / initialize !^x;4@Ejm
DECLARE @OriginalSize int P-_2IZiz
SELECT @OriginalSize = size _qf$dGqc
FROM sysfiles p[8H!=`K
WHERE name = @LogicalFileName _g]h \3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + = e"RE/q2
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _, r6t
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !q[r_wL
FROM sysfiles (R|_ 6[zy
WHERE name = @LogicalFileName )4;$;a1
CREATE TABLE DummyTrans GQ8A}gwH
(DummyColumn char (8000) not null) "Q.KBX v/
DECLARE @Counter INT, n|'}W+
@StartTime DATETIME, dsG:DS`q
@TruncLog VARCHAR(255) wZs jbNf`K
SELECT @StartTime = GETDATE(), \uyZl2=WWa
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *K'#$`2
DBCC SHRINKFILE (@LogicalFileName, @NewSize) +=Y$v2BZA3
EXEC (@TruncLog) -d]v6q'1
-- Wrap the log if necessary. 0 /)OAw"m
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired i4dy0jfN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #PGpB5vnaA
AND (@OriginalSize * 8 /1024) > @NewSize (
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BEGIN -- Outer loop. NcyE_T
SELECT @Counter = 0 i$g6C
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \!Wph5wA
BEGIN -- update zLSha\X
INSERT DummyTrans VALUES ('Fill Log') ~j36(`t
DELETE DummyTrans m5%E1k$=
SELECT @Counter = @Counter + 1 TNF+yj-|X:
END iI$;%uY3g
EXEC (@TruncLog) k fY0u
END \GdsQAF"
SELECT 'Final Size of ' + db_name() + ' LOG is ' + w?JM;'<AYQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 87-z=>IU
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ] ]lN[J
FROM sysfiles l3Wh&*0
WHERE name = @LogicalFileName U}<' [o
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DROP TABLE DummyTrans 5,#aN}v#?
SET NOCOUNT OFF [l*;+N+
8、说明:更改某个表 APv&
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exec sp_changeobjectowner 'tablename','dbo' &`2$,zX#
9、存储更改全部表 c9ea%7o{0a
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _X~xfmU
@OldOwner as NVARCHAR(128), }Sh3AH/
@NewOwner as NVARCHAR(128) /y3Lc.-
AS }PX8#C_P
DECLARE @Name as NVARCHAR(128) fU>4Ip1?y/
DECLARE @Owner as NVARCHAR(128) `G<|5pe
DECLARE @OwnerName as NVARCHAR(128) o9+fAH`D
DECLARE curObject CURSOR FOR H03R?S9AQ
select 'Name' = name,
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'Owner' = user_name(uid) *EF`s~
from sysobjects
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where user_name(uid)=@OldOwner o<L=l Q
order by name _}l7f
OPEN curObject axM(3k.n
FETCH NEXT FROM curObject INTO @Name, @Owner b" kL)DL1L
WHILE(@@FETCH_STATUS=0) z]R% A:6K
BEGIN *@fVog r^
if @Owner=@OldOwner s(r1q$5
begin n*m"yp
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~kOXMLRg
exec sp_changeobjectowner @OwnerName, @NewOwner ZJOO*S
end )P#xny2
-- select @name,@NewOwner,@OldOwner xsRu~'f
FETCH NEXT FROM curObject INTO @Name, @Owner Y.#:l<
END Z"d21D~h9`
close curObject )E}eK-Yu
deallocate curObject la_FZ
GO VX'G\Zz@h|
10、SQL SERVER中直接循环写入数据 yUX<W'-Hev
declare @i int >8EmfjUoc
set @i=1 ;edt["Eu
while @i<30 8.tp#x,A
begin L[. )!c8k
insert into test (userid) values(@i) p sAr>:\3
set @i=@i+1 _YA;Nd#%k
end wT&P].5n
小记存储过程中经常用到的本周,本月,本年函数 K{`3,U2Wx
Dateadd(wk,datediff(wk,0,getdate()),-1) <xwaFZ
Dateadd(wk,datediff(wk,0,getdate()),6) "64D.c(r$
Dateadd(mm,datediff(mm,0,getdate()),0) iz:O]kI
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]Vd1fkXO0
Dateadd(yy,datediff(yy,0,getdate()),0) HC
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) QV_Ep8
上面的SQL代码只是一个时间段 _MzdbUb5,
Dateadd(wk,datediff(wk,0,getdate()),-1) nT%<!/}!
Dateadd(wk,datediff(wk,0,getdate()),6) s%@HchZ 1
就是表示本周时间段. U>a~V"5,u
下面的SQL的条件部分,就是查询时间段在本周范围内的: $j'8Z^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) BF(Kaf;<t.
而在存储过程中 SAUG+{Uq
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1V;m8)RF
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Rqun}v}