Newbie question

[Michael Thomas]

All I want to know is the sytax for "mysql_result()" and I can't find it on this site to save my life.

Also:

$sql = mysql_query("SELECT {$prefix}categories.id, {$prefix}categories.name, COUNT({$prefix}subcategories.id) AS subcategories FROM {$prefix}categories LEFT JOIN {$prefix}categories AS {$prefix}subcategories ON {$prefix}subcategories.ref = {$prefix}categories.id WHERE {$prefix}categories.ref = $c GROUP BY {$prefix}categories.id ORDER BY {$prefix}categories.name");
for ($x = 0; $x < $n_subcategories; $x++){
$subcategories[$x]["subcategories"] = mysql_result($sql, $x, "subcategories");
};

This bit of code is what I'm trying to understand...I have a general knowledge of programming but this gets too specific to mysql for me to follow it. I understand that the select statement is getting a list of all categories and the number of subcategories they have and it's then putting that into an array, but I don't get why the $x is in the mysql_result() nor do I understand LEFT JOIN with "subcategories" when "subcategories" isn't a real table it's.

If anyone could set me straight here it would be greatly appreciated.