How to return multiple results from an array of options?

I have an array of data :

$ary = new array(
    array("domain"=>"domain1", "username"=>"username1"),
    array("domain"=>"domain1", "username"=>"username2"),
    array("domain"=>"domain2", "username"=>"username3"),
);

I need to use this data to retrieve data from a MySql database with the following table structure (simplified for illustration).

domain_table
    domain_id
    domain

user_table
    user_id
    user

stuff_table
    stuff_id
    ... details

link_table
    link_id
    user_id   -- The user we are searching for connections on
    connected_user_id   -- from the array above
    stuff_id

I need to fetch every row in the stuff table for a single user_id that also has a connected_user_id from the array.

I'm using PDO

There may be hundreds (possibly thousands) of entries in $ary.

I could generate a very large query by looping thorugh the array and adding loads of joins. I could perform a single query for each row in $ary. I could create a temporary table with $ary and use a join. Something else?

What is the best way - fastest processor time without being too arcane - to achieve this?

1. perform a single query for each row - bed way because of small speed
2. many joins better then 1.
3. if it is possible - make view & use it.

If your entire dataset is HUGE and doesn't fit in memory, joins shouldn't be your choice.

Do sequential selects. Select rows from your link_table, gather user_id's out of the result in PHP. Then select rows from user_table using "where user_id in (?)". Handle grouping of results in PHP.

Even with large tables selects by key will be fast. And having 2-5 selects instead of 1 select is not a problem.

Joins will be fast while your DB fits into RAM. Then problems arise.