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Jun 14, 2014 Replied to a topic by hellohacker › 程序员 › 用计算结果给从数据库数据排序的问题 |
SELECT * , ( 2 - SUM( zhongjiang ) / COUNT( user_id ) ) AS psort
FROM `zhongjiang`
WHERE 1
GROUP BY user_id
ORDER BY psort DESC
FROM `zhongjiang`
WHERE 1
GROUP BY user_id
ORDER BY psort DESC
Sep 8, 2013 Replied to a topic by ovear › PHP › 关于PHP FOREACH的一个问题 |
第一个循环结束之后
foreach ($ww as &$v) {}
$v是指向$ww 最后一个值的引用
此时如果对 $v 赋值都会改变 $ww 最后一个元素的值
例如 ：$v = 'someValue';
则：
$ww = Array
(
[0] => 123,
[1] => 456,
[2] => 'someValue'
)
第二个循环遍历逐个将 $qq 的元素赋值给 $v;
循环结束时刚好是 $v = $qq[2] = 3
foreach ($ww as &$v) {}
$v是指向$ww 最后一个值的引用
此时如果对 $v 赋值都会改变 $ww 最后一个元素的值
例如 ：$v = 'someValue';
则：
$ww = Array
(
[0] => 123,
[1] => 456,
[2] => 'someValue'
)
第二个循环遍历逐个将 $qq 的元素赋值给 $v;
循环结束时刚好是 $v = $qq[2] = 3
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