I have a JOIN error that is rather opaque...at least to me. I've using other JOIN queries on this project, which seem very similar to this one, which looks like: SELECT S.subjectid,STY.studyabrv,labID,boxnumber,wellrow,wellcolumn FROM DNASample D, IBG_Studies STY, Subjects S, ibg_projects P LEFT OUTER JOIN ibg_ps_join IPJ USING (dnasampleid) WHERE D.subjectidkey=S.id AND STY.studyindex=D.studyindex AND IPJ.projects_index=P.ibg_projects_index ORDER BY studyabrv,boxnumber,wellcolumn,wellrow But when I run it I get this error: ERROR: column "dnasampleid" specified in USING clause does not exist in left table I am rather mystified by this, since this field is definitely in the dnasample table, as the primary key. Nor do not see how to start debugging such an error. Any suggestions appreciated... --Rick -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general