Question

            [0] => Array
                (
                    [food_id] => 33
                    [food_category_id] => 51
                )

            [1] => Array
                (
                    [food_id] => 33
                    [food_category_id] => 12
                )

            [2] => Array
                (
                    [food_id] => 34
                    [food_category_id] => 62
                )

            [3] => Array
                (
                    [food_id] => 35
                    [food_category_id] => 2
                )

            [4] => Array
                (
                    [food_id] => 35
                    [food_category_id] => 80
                )

            [5] => Array
                (
                    [food_id] => 35
                    [food_category_id] => 99
                )

这是生成数组的查询

$query = $this->writedb->query("SELECT * FROM `food_to_category` WHERE food_id IN ( " . $implode_data . " )");

上面是输出，但是如果food_id相同，如何将数组组合成1个数组？现在显示的是所有独立数组，如果food_id相同，想合并

Answer 1

您可以使用GROUP BY语句轻松完成此操作，但还必须使用GROUP CONCAT来保存所有类别ID

https://dev.mysql.com/doc/refman/8.0/en/group-by-modifiers.html

"SELECT food_id, GROUP_CONCAT(food_category_id) FROM `food_to_category` WHERE food_id IN ( " . $implode_data . " ) GROUP BY food_id"

我会产生相似的结果

[3] => Array
 (
      [food_id] => 35
      [food_category_id] => "2,80,99"
 )

如果要将类别ID作为数组，则可以用逗号将其爆炸

如果主值相同，则合并数组

1 个答案: