PHP和MySQL - 如果值不为null则循环查询[关闭]

Question

I currently have a database table setup like so:

| id | thing_id | value

The "thing_id" relates to a unique ID within the same table.

I'm trying to create a function (in PHP) that will run a query against the MySQL database, dump that information into an array, and if "thing_id" is NOT NULL it will loop back and run the query again, and add the information on to the existing array. This will continue until the "thing_id" is NULL.

How can I go about doing this? Btw, I'm designing this on top of WordPress.

The following below works, but I feel like there is some better way to do this. How can I simplify this and make it not hog resources? Here is what I have:

        $related_thingsSql = "
                            SELECT $thingsDB.value, $thingsDB.thing_id, $thingsDB.id
                            FROM $thingsDB
                            WHERE $thingsDB.id = '$related_thing_id'
                            ";              

        $related_things = $wpdb->get_results( "$related_thingsSql" );

        foreach ($related_things as $related_thing) {
            $related_thing_name[] = $related_thing->value;  
            $related_thing_id2[] = $related_thing->id;
            $related_thing_id = $related_thing->thing_id;                   
        }
        while ($related_thing_id != NULL) {
            $related_thingsSql2 = "
                                    SELECT $thingsDB.value, $thingsDB.thing_id, $thingsDB.id
                                    FROM $thingsDB
                                    WHERE $thingsDB.id = '$related_thing_id'
                                ";                                              
            $related_things = $wpdb->get_results( "$related_thingsSql2" );
            foreach ($related_things as $related_thing) {
                array_unshift($related_thing_name, $related_thing->value);
                array_unshift($related_thing_id2, $related_thing->id);
                $related_thing_id = $related_thing->thing_id;
                if (empty($related_thing->thing_id)) {
                    $related_thing_id = NULL;   
                }
            }
        }
        $related_things_length = count($related_thing_name);

        for ($x = 0; $x < $related_things_length; $x++) {
            echo ' > <a href="' . site_url() . '?id=' . $related_thing_id2[$x] . '">' . $related_thing_name[$x] . '</a>';
        }

Answer 1

I figured out a way that works. I feel like this way is really sloppy, but it works. If anyone has any suggestions on how to improve this, feel free.

            $related_thingsSql = "
                                SELECT $thingsDB.value, $thingsDB.thing_id, $thingsDB.id
                                FROM $thingsDB
                                WHERE $thingsDB.id = '$related_thing_id'
                                ";              

            $related_things = $wpdb->get_results( "$related_thingsSql" );

            foreach ($related_things as $related_thing) {
                $related_thing_name[] = $related_thing->value;  
                $related_thing_id2[] = $related_thing->id;
                $related_thing_id = $related_thing->thing_id;                   
            }
            while ($related_thing_id != NULL) {
                $related_thingsSql2 = "
                                        SELECT $thingsDB.value, $thingsDB.thing_id, $thingsDB.id
                                        FROM $thingsDB
                                        WHERE $thingsDB.id = '$related_thing_id'
                                    ";                                              
                $related_things = $wpdb->get_results( "$related_thingsSql2" );
                foreach ($related_things as $related_thing) {
                    array_unshift($related_thing_name, $related_thing->value);
                    array_unshift($related_thing_id2, $related_thing->id);
                    $related_thing_id = $related_thing->thing_id;
                    if (empty($related_thing->thing_id)) {
                        $related_thing_id = NULL;   
                    }
                }
            }
            $related_things_length = count($related_thing_name);

            for ($x = 0; $x < $related_things_length; $x++) {
                echo ' > <a href="' . site_url() . '?id=' . $related_thing_id2[$x] . '">' . $related_thing_name[$x] . '</a>';
            }