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回复讨论(解决方案)

mysql 排序问题

Jun 23, 2016 pm 01:46 PM

mysql 查询出一个数据列表 这个数据列表是分页的 比如说5个记录一页

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$page = $_REQUEST['page'];select * from user limit ($page-1)*5,5;

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然后查询的数组比如说为$user_list 然后循环这个user_list

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foreach($user_list as $k=>$v){    // 然后根据某函数比如说 aa 计算出一个新的字段cc    $user_list[$k]['cc'] = aa($v['id']);}

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然后想按照cc这个字段排序user表 遇到的问题是 列表是分页的 第一页排序是正常 从小

到大排序 但是点击第二页又会出现从小到大排序 而不是已整体为依据 排序整个数据

cc 是经常变的字段,不能存到数据库 必须经由计算得出 请教一下大家有什么好的解决方法


回复讨论(解决方案)

可以在查询的时候把你的计算公式aa嵌套进语句中算出CC(如果aa不太复杂的话) 然后直接按CC排序即可

可以在查询的时候把你的计算公式aa嵌套进语句中算出CC(如果aa不太复杂的话) 然后直接按CC排序即可

但是比如说我写的这个sql distance的值就计算不出来

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$sql = "select id,avg_point,name,xpoint,ypoint,index_img,dp_count,deal_cate_id,ratio,note ,".intval(GetDistance($ypoint,$xpoint,'ypoint','xpoint')*1000)." as distance  from ".DB_PREFIX."supplier_location where ".$where;

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//把你的aa函数写成mysql的函数,然后用sqlselect *,aa(id)cc from table order by cc desc;

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//把你的aa函数写成mysql的函数,然后用sqlselect *,aa(id)cc from table order by cc desc;

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aa函数是自己写的一个函数 实现特定的功能 mysql里没有

那应该怎么实现像这样的msyql自定义函数 aa(变量1,变量2,表字段1,表字段2)

那应该怎么实现像这样的msyql自定义函数 aa(变量1,变量2,表字段1,表字段2)



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//你的aa函数就要4个变量select *,aa(变量1,变量2,字段1,字段2)cc from table order by cc desc;

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http://www.baidu.com/s?wd=mysql%20%E8%87%AA%E5%AE%9A%E4%B9%89%E5%87%BD%E6%95%B0&rsv_spt=1&issp=1&f=8&rsv_bp=0&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=3&rsv_sug4=97&rsv_sug1=3&rsv_sug2=0&inputT=2568

使用create temporary table temp
创建一个临时表,然后把cc计算好后作为字段保存在temp中,然后再对临时表排序,分页。

使用create temporary table temp
创建一个临时表,然后把cc计算好后作为字段保存在temp中,然后再对临时表排序,分页。

  谢谢你的热心回答, cc  这个实际上是根据用户的位置得出的一系列商家距他的距离    如果用临时的表话  那多个用户会数据存在太多   

你只对读取到的部分数据进行了计算,当然排序的效果就不是预期的了
如果你是需要按距离排序,那么可以这样做:
假定表中有 X、Y 字段分别保存有商家的经纬度
$x、$y 表示用户的经纬度
则有 select * from user  ORDER BY abs($x-X), abs($y-Y) limit ($page-1)*5,5;

一定要全部??排序後再分?。否?就不能??了。

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