php - 根据最大日期获取每组的最新行

Question

我试图从每个日期最大的组中选择一个。

我正在尝试用这个波纹管做

|NO | effective   | price     |  level_one| level_two
+---+-------------+----------+|+++++++++++|++++++++++++
|1  | 2011-12-01  |  34       |     1     |    2
|2  | 2011-16-01  |  34       |     1     |    2
|3  | 2011-18-01  | 3434      |     1     |    2
|4  | 2011-16-01  | 3554      |     1     |    3

结果应该是

|NO | effective   | price     |  level_one| level_two
+---+-------------+----------+|+++++++++++|++++++++++++
|3  | 2011-18-01  | 3434      |     1     |    2
|4  | 2011-16-01  | 3554      |     1     |    3

结果来了

|NO | effective   | price     |  level_one| level_two
+---+-------------+----------+|+++++++++++|++++++++++++
|3  | 2011-12-01  | 34        |     1     |    2
|4  | 2011-16-01  | 3554      |     1     |    3

尝试过

$price = App\Price::with('others')
    ->orderBy('effective', 'Desc')
    ->groupBy('level_one','level_two')
    ->get();

Answer 1

日期格式有问题。通常eloquent和mysql使用Y-m-d日期格式。

像这样使用:

$price = App\Price::with('others')
    ->orderByRaw("DATE_FORMAT(effective,'%Y-%d-%m') DESC")
    ->groupBy('level_one','level_two')
    ->get();