mySQL php查询 - 新闻/朋友提要

Question

I want to show a user the recent uploads from their friends.

I have the users friends id's in an array:

$friends

A user could have, potentially, thousands of friends.

I can select the uploads from 1 of a users friends with:

$row = $mysqli->query("SELECT * FROM photos 
                       WHERE uploader_id =  ".$friend." 
                       ORDER BY date_uploaded 
                       DESC LIMIT ".$page.", 25");

But I need to find all of a users friends uploads. I thought about doing this in a loop iterating over the $friends array, but then I'd be potentially running thousands of mysql queries.

How can I do this most efficiently?

so to clarify:

search a 'photos' table for photos which are uploaded by specific users(friends), held in $friends variable, sort by date_uploaded and limit to x results so I can have pages 1, 2, 3 etc.

Answer 1

Use implode to join array elements with a comma and use MySQL's IN clause.

$row = $mysqli->query("SELECT * FROM photos 
                   WHERE uploader_id IN (". implode(',' $friends) .") 
                   ORDER BY date_uploaded 
                   DESC LIMIT ".$page.", 25");

Make sure your $friends array doesn't contain any unsanitized input. As it stands right now you are open to SQL injection if $friends is dependent on user input in any way.