``` $box = array( 0 =>array( 'boxnum' => 1, 'record' => 66 ), 1 =>array( 'boxnum' => 2, 'record' => 66 ), 2 =>array( 'boxnum' => 3, 'record' => 66 ) ) //求boxnum这一列的最大值 $max = 0; foreach ($box as $key => $val) { $max = max($max , $val['boxnum']); } //求boxnum这一列的最小值 $min = 0; foreach ($box as $key => $val) { $min = min($min , $val['boxnum']); } ````