MySQL多行结果合并为一行group

在做一个项目的用户列表的时候，需要将一个用户的多辆车放在一行显示，但是普通查询出来的结果是：

Array ( [0] => Array ( [id] => 29 [user_id] => 1 [car_no] => 234567 ) [1] => Array ( [id] => 21 [user_id] => 1 [car_no] => 23565 ) [2] => Array ( [id] => 23 [user_id] => 1 [car_no] => 12345 ) [3] => Array ( [id] => 28 [user_id] => 1 [car_no] => 124455 ) [4] => Array ( [id] => 6 [user_id] => 1 [car_no] => 12345 ) [5] => Array ( [id] => 7 [user_id] => 2 [car_no] => 22 ) [6] => Array ( [id] => 3 [user_id] => 2 [car_no] => 粤T863 ) [7] => Array ( [id] => 25 [user_id] => 3 [car_no] => 12345 ) );

但是我们想要的结果是：

Array( [0] => Array ( [user_id] => 8 [login] => 18620982882 [car_no] => Array ( [0] => 粤A123 ) ) [1] => Array ( [user_id] => 7 [login] => [car_no] => Array ( [0] => 粤T456 [1] => 123456 ) ) [2] => Array ( [user_id] => 2 [login] => 13318029123 [car_no] => Array ( [0] => 粤T863 [1] => 22 ) ) [3] => Array ( [user_id] => 1 [login] => 15088138542 [car_no] => Array ( [0] => 12345 [1] => 23565 [2] => 12345 [3] => 124455 [4] => 234567 ) ) )

我之前的方法是：

private function group_sort($unique, $num, $data) { foreach ($unique as $key => $value) { for ($i = 0; $i < $num; $i++) { if ($data[$i]['user_id'] == $value) { $data_format[$key]['user_id'] = $data[$i]['user_id']; $data_format[$key]['login'] = $data[$i]['login']; $data_format[$key]['car_no'][] = $data[$i]['car_no']; } } } return $data_format; }

一个一个遍历，进行重组聚合，也可以到到效果，但是效率低下，代码也比较复杂，今天查阅资料发现一个简单的方法，mysql本身有这个功能，可以把多个结果整合为一行，默认用逗号隔开，sql语句如下：

select user_id,group_concat(car_no) as car_no from mf_car_info group by user_id;

产生的结果：

Array ( [0] => Array ( [user_id] => 1 [car_no] => 12345,23565,12345,124455,234567 ) [1] => Array ( [user_id] => 2 [car_no] => 粤T863,22 ) [2] => Array ( [user_id] => 3 [car_no] => sdfa,12345 )

这个就简单多了，直接遍历分割一下即可：

foreach ($data as $key => $value) { $data[$key]['car_no'] = explode(',', $value['car_no']); } echo "<pre>"; print_r(json_encode($data)); echo "</pre>";

完整代码如下：

<?php $dsn = 'mysql:dbname=xxxx;host=192.xxx.1.xxx;port=3306'; $username = 'ysp'; $password = '123456'; try { $pdo = new PDO($dsn, $username, $password); $pdo->exec('set names utf8'); $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); } catch (PDOException $e) { die('Could not connect to the database: ' . $e); } $statement = "select id,user_id,group_concat(car_no) as car_no from mf_car_info group by user_id"; $rows = $pdo->query($statement); //获取总行数 // print_r($rows->rowCount()); //获取所有结果 $data = $rows->FetchAll(); foreach ($data as $key => $value) { $data[$key]['car_no'] = explode(',', $value['car_no']); } echo "<pre>"; print_r(json_encode($data)); echo "</pre>"; exit;

把不同品牌下面的所有应用按照品牌汇集输出：

SELECT brand, GROUP_CONCAT(DISTINCT(registed_app)) FROM `users` GROUP by brand；