PHP递归类返回NULL [英] PHP Recursive class returning NULL

问题描述

拜托朋友，我的代码需要帮助.

Please friends, I need help for my code.

我的 searchParent 函数在多次执行 self :: 时总是返回NULL

My searchParent function always returns NULL when it executes the self:: more than once

class Search {
    public function listParents() {
        $sql = "SELECT id FROM parents";
        return pg_query($sql);
    }

    public function searchParent($id) {
        $parents= $this->listParents($con);
        while ($r = pg_fetch_array($parent)){
            if ($id === $r['id_parent']){
                return $id;
            } 
        }
        $sql = "SELECT id_parent FROM parent WHERE id_parent = $id";
        $query = pg_query($sql);
        $result = pg_fetch_array($query);

        self::searchParent($result['id_parent']);
    }
}

我的电话，假设父表中有数字230

My call, assuming there is the number 230 in the parent table

$id = $search->searchParent(230);

推荐答案

您需要弄虚函数的 return 值.

在调用 self :: searchParent 之前，应添加return语句:

Before calling the self::searchParent you should add return statement:

return self::searchParent($result['id_parent']);

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