MySQL, left join only first row

MySQL, left join only first row:
                LEFT JOIN     fmcontract_rate_table AS rt
                    ON rt.ApptCategory =(SELECT ApptCategory  FROM fmcontract_rate_table WHERE
                    ApptCategory=hasRanks.Rank AND offered.Term >=StartTerm 
                   AND offered.Term  <EndTerm
                    ORDER BY rt.StartTerm LIMIT 1
                    )