Consolidating rows in an associative array to merge specific values

Question

I am retrieving an array of associative arrays from my sql

for ex -

Array( [0]=>{Array([user_id] => 6920 [user_fname] => Jay [user_lname] => Martin [user_skill] => Java} 
[1]=> {Array([user_id] => 6920 [user_fname] => Jay [user_lname] => Martin [user_skill] => C++} 
[2]=> {Array([user_id] => 6920 [user_fname] => Jay [user_lname] => Martin [user_skill] => php}

and this goes on for all the users , how can i consolidate these three rows to get a single row with all the skills.PHP

answer i want ->Array( [0]=>{Array([user_id] => 6920 [user_fname] => Jay [user_lname] => Martin [user_skill] => Java , C++ ,PHP}