将非MySQL列表/数组/数据与MySQL行进行比较？

Question

I'm developing an iOS social networking app. I'm currently building "Find Friends" section.

I have a "users" table which is something like this:

-user_id  -user_name  ... -twitter_id   -facebook_id   -instagram_id
948913    yagiz           2134421       2132412        4314124312

Now for example when I try to find friends, app does this in the background:

• Get the list of whole followings of current user from selected social networking app(Twitter/Facebook/Instagram). Response is a simple array which consists of user ids.

• For each Twitter/Facebook/Instagram id run a query that checks if it is in app database.

Currently this works well. But I kinda think that this isn't efficient. Because if the user follows 5K people on Twitter/Facebook/Instagram app runs 5K query.

So I'm asking which is the best way to compare non MySQL list/array/data with MySQL rows?

Answer 1

You can perform a single query using

WHERE ... IN('1', '2') 

If you have an array of the ids , you can do it like this:

$twitterIds = array(
    1234,
    1235,
    1236
);

// $twitterIdString = '1234','1235','1236'
$twitterIdString = "'" . implode("','", $twitterIds) . "'";

// $queryStub = WHERE `-twitter_id` IN('1234','1235','1236')
$queryStub = "WHERE `-twitter_id` IN(" . $twitterIdString . ")";

This will return only the twitter users that are in your database.