When I run a zipcode search for local circles, this is my result:
user warning: Column 'nid' in field list is ambiguous query: SELECT COUNT(DISTINCT (nid)) AS count FROM node n INNER JOIN location l ON n.vid = l.eid INNER JOIN node_access na ON na.nid = n.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 0 AND na.realm = 'og_public') OR (na.gid = 1 AND na.realm = 'term_access'))) AND ( l.type ='node' AND l.latitude > 33.3339469554 AND l.latitude < 34.7811750446 AND l.longitude > -118.539069162 AND l.longitude < -116.792190838 AND (IFNULL(ACOS(0.828475372893*COS(RADIANS(latitude))*(-0.464310841345*COS(RADIANS(longitude)) + -0.885672311078*SIN(RADIANS(longitude))) + 0.560025496303*SIN(RADIANS(latitude))), 0.00000)*6371406.93738) < 80467.35) in /home/spiralscouts.org/public_html/includes/database.mysql.inc on line 172.