query help

[Protoman]

I'm trying to write an SQL query but I really don't know what I'm doing

PHP Code:

SELECT userfield.field66, user.username FROM userfield INNER JOIN Orders ON userfield.userid=user.userid 


I want it to do this: (probably in a couple different queries)

take $variable and look for matches in table userfield column field66

then return all matching usernames of members with that userfield value in an array if possible.
(maybe i'll end up moving this to service requests) :ermm: