内部功能内部功能虽然每层只触发一次

Question

考虑这个（简化的）代码...调用函数getLevelOne，运行正常，调用getLevelTwo，运行正常，然后停止，而不继续在getLevelOne中调用的while ...它的编写方式，你是假设将为$ list1（2,4,5,6）中的每个数字调用第二个函数...我错过了什么？

$list1 = "2,4,5,6";
$table1 = 'thistable';
getLevelOne($list1, $table1);

function getLevelOne($list1, $table1){
    $q = "select * from $table1 where id IN ('$list1')";
    $r = mysqli_query($db, $q);
    while($row = mysqli_fetch_array($r)){
        echo 'oh';
        $table2 = 'nexttable';
        $list2 = $row[$table2];
        getLevelTwo($list2, $table2);
    }

}

function getLevelTwo($list2, $table2){
    $q2 = "select * from $table2 where id IN ('$list2')";
    $r2 = mysqli_query($db, $q2);
    while($row2 = mysqli_fetch_array($r2)){
        echo 'shit';
    }
}