I have three tables. The appraisers table stores an appraiser's name and email, the appraiserinfo table stores their address, phone, fax and other contact information, and the citylistings table keeps track of which cities an appraiser will appraise in.

This query is working great:

SELECT *
FROM appraisers
INNER JOIN citylistings ON citylistings.zipid=appraisers.zipid
INNER JOIN appraiserinfo ON appraiserinfo.zipid=appraisers.zipid
WHERE ( ( ( citylistings.st = 'CA' ) AND ( citylistings.city = 'Los Angeles' )) ) AND ( ( ( appraiserinfo.licensestate = 'CA' ) ) )
ORDER BY citylistings.timelisted ASC

Now I want to get information from a fourth table, the localareas table, which has information about zipcodes i.e. zipcode, latitude, longitude. I need to retrieve the latitude and longitude for each appraisers zipcode and calculate their distance from a predetermined latitude and longitude, so I thought the following the would work:

SELECT *, acos(sin(localareas.latitude*0.01745329252)*sin(40.4192*0.01745329252) + cos(localareas.latitude*0.01745329252)*cos(40.4192*0.01745329252)*cos(localareas.longitude*0.01745329252 - -111.565*0.01745329252))*3958.75586 AS distance
FROM appraisers
INNER JOIN citylistings ON citylistings.zipid=appraisers.zipid
INNER JOIN appraiserinfo ON appraiserinfo.zipid=appraisers.zipid
INNER JOIN localareas ON localareas.zipcode=appraiserinfo.zip
WHERE ( ( ( citylistings.st = 'CA' ) AND ( citylistings.city = 'Los Angeles' )) ) AND ( ( ( appraiserinfo.licensestate = 'CA' ) ) )
ORDER BY distance

Unfortunately the query returns no rows. I'm clearly not understanding something about how joins operate. Would somebody care to enlighten me?