Create a multidimensional array with PHP and MySQL

I am new to PHP and am looking at efficient ways to return data from the database. Lets say I have a UserProfile table that has a one to many relationship with UserInterest and UserContact:

Select p.Id, p.FirstName, p.LastName, i.Name as Interests, c.Email, c.Phone
from UserProfile p
left join UserInterest i on p.Id = i.UserProfileId
left join UserContact c on p.Id = c.UserProfileId
where p.Id = 1

An efficient way to retrieve data would be to create a multidimensional array such as:

$user = array(  "FirstName" => "John",
                "LastName" => "Doe",
                "Gender" => "Male",
                "Interests" => array(
                    "Hiking",
                    "Cooking"),
                "Contact" => array(
                    "Email" => "john.doe@gmail.com",
                    "Phone" => "(555) 555-5555"));

I can't seem to get my head around how this would be constructed in PHP. For simple data like interests I could use group_concat(i.Name) as Interests in the query to return interests back as a comma separated list in a single row, however, for an associative array such as Contact, I'd like to be able to get a handle on each key in the array using $user['Contact']['Email'].

From a "Best Practices" standpoint, I would assume that constructing an array like this in one query is a lot better than hitting the database multiple times to retrieve this data.

Thanks!

Neil

---

You can construct this array in one pass through the data returned by your query. In pseudo-code:

for each row
     $user["FirstName"] = row->FirstName;
     $user["LastName"] = row->LastName;
     $user["Interests"][] = row->Interests;
     $user["Contact"]["Email"] = row->Email;
     $user["Contact"]["Phone"] = row->Phone;
next

The syntax $user["Interests"][] = $data is valid PHP code. It is equivalent to array_push($user["Interests"], $data).