CREATE TRIGGER TRG_SUM_PERSONCOUNT
AFTER INSERT OR UPDATE OR DELETE ON CASES
BEGIN
    UPDATE geo_m_count g
       SET person_count = (
            SELECT COUNT(*)
              FROM cases c
             WHERE g.oacode LIKE c.oacode
               AND g.sex = c.sex
               AND c.ageyears BETWEEN g.age_start and g.age_end
           )
END;
/

##</code><code>##

SELECT cause_of_death
      ,oa_code
      ,gender
      ,MIN( date_death - date_birth ) AS age_start
      ,MAX( date_death - date_birth ) AS age_end
      ,COUNT( * )
  FROM cases
 GROUP BY cause_of_death
         ,oa_code
         ,gender
;