我们知道,rowid和rownum在Oracle中都是可以被当做伪劣使用的,主要用来定位表中特定的记录,但它们是有区别的,rowid是和行记录在Oracle 8以下,rowid(也叫受限rowid)为:FFFF.BBBBBBBB.RRRR,,占用6个字节(10bit file#+22bit+16bit),但是,为了扩充的需要,如数据文件的扩充,现在的rowid改为:OOOOOOFFFBBBBBBRRR,占用10个字节(32bit+10bit rfile#+22bit+16bit)。其中,O是Object号,F是File号,B是Block号,R是Row号。...
Oracle中的ROWNUM rowid 以及MySQL中实现rownum功能类似的语句 http://gong-10140.iteye.com/blog/745685 1.ROWNUM的使用——TOP-N分析 使用SELECT语句返回的结果集,若希望按特定条件查询前N条记录,可以使用伪列ROWNUM。 ROWNUM是对结果集加的一个伪列,即Oracle中的ROWNUM rowid 以及MySQL中实现rownum功能类似的语句http://gong-10140.iteye.com/blog/7456851.ROWNUM的使用——TOP-N分析 使用SELECT语句返回的结果集,若希望按...
初始化表结构 DROP TABLE IF EXISTS `data` ; CREATE TABLE `data` ( `dates` varchar ( 255 ) CHARACTER SET utf8 DEFAULT NULL , `id` int ( 11 ) DEFAULT NULL , `result` varchar ( 255 ) CHARACTER SET utf8 DEFAULT NULL ); INSERT INTO `data` ( `dat初始化表结构DROP TABLE IF EXISTS `data`; CREATE TABLE `data` (`dates` varchar(255) CHARACTER SET utf8 DEFAULT NULL,`id` int(11) DEFAULT NULL,`result` varchar(255...
MySQL 几乎模拟了 Oracle,SQL Server等商业数据库的大部分功能,函数。但很可惜,到目前的版本(5.1.33)为止,仍没有实现ROWNUM这个功能。下面介绍几种具体的实现方法.建立实验环境如下mysql> create table tbl ( -> id int primary key, -> col int -> );Query OK, 0 rows affected (0.08 sec)mysql> insert into tbl values -> (1,26), -> (2,46), -> (3,35), -> (4,68), -> (5,93), -> (6,...
bitsCN.com MySQL 如何实现 Oracle 的 ROWNUM2010/01/28 23:56mysql> SELECT * FROM frutas; +-----------+----------+ | nombre | color | +-----------+----------+ | fresa | rojo | | platano | amarillo | | manzana | verde | | uva | verde | | pera | verde | | mandarina | naranja | | melocoton | marron | | limon | amarillo | +-----------+----------+ 8 rows in set...
bitsCN.com Sql:SELECT @rownum:=@rownum+1 AS rownum,a.order_id ,case when a.Ordered =1 then 已分单 end as Ordered,a.printed ,a.order_sn ,a.user_id ,b.user_name ,a.consignee ,a.tel ,a.mobile ,a.address ,a.pay_name ,a.goods_amount ,a.shipping_fee ,FROM_UNIXTIME(a.add_time+8*3600) ,a.postscript ,a.best_timeFROM (SELECT @rownum:=0) r,xj_order_info a INNER JOIN xj_users b on a.user_id =b.user_idwhere (...
表: 数据: 1. 用户可以多次考试,以最新的为准SELECTt.* FROM( SELECT * FROM t_demo ORDER BY begin_time DESC ) t GROUP BYt.user_id ORDER BYt.score DESC 结果: 2. 排名:分数一样的排名一样SELECTobj.user_id,obj.score,obj.begin_time, CASEWHEN @rowtotal = obj.score THEN@rownum WHEN @rowtotal := obj.score THEN@rownum := @rownum + 1 WHEN @rowtotal = 0 THEN@rownum := @rownum + 1 END AS rownum FROM...
我问了一个关于为查询结果创建临时/虚拟ID的问题,mysql & php: temporary/ virtual ids for query results? 我几乎得到了这个链接,http://craftycodeblog.com/2010/09/13/rownum-simulation-with-mysql/ 我设法列出每一行,SELECT u.pg_id AS ID, u.pg_url AS URL, u.pg_title AS Title, u.pg_content_1 AS Content, @rownum:=@rownum+1 AS rownumFROM (SELECT pg_id, pg_url,pg_title,pg_content_1FROM root_pagesWHERE root_pag...
我有以下功能的问题:function get_organization_score($org_id) {$sql1 = "SET @rownum := 0";$sql2 = "SELECT rank, xp_total FROM (SELECT @rownum := @rownum + 1 AS rank, g_org.id AS org_id,(Sum(g_npc.xp) + (Sum(g_npc.level)*128)) AS xp_total FROM g_orgLEFT JOIN g_npc ON g_org.id = g_npc.g_org_id GROUP BY g_org.idORDER BY xp_total DESC) as result WHERE org_id='".$org_id."'";mysql_query($sql1);$result = ...