Question

If I have the table “members” (shown below), how would I go about getting the record of the first occurrence of a membership_id (Oracle).

Expected results

123                 John                      Doe                      A       P
313                 Michael                   Casey                    A       A
113                 Luke                      Skywalker                A       P

Table – members

membership_id       first_name                last_name                status  type
123                 John                      Doe                      A       P
313                 Michael                   Casey                    A       A
113                 Luke                      Skywalker                A       P
123                 Bob                       Dole                     A       A
313                 Lucas                     Smith                    A       A

Answer 1

SELECT membership_id,
       first_name,
       last_name,
       status,
       type
  FROM( SELECT membership_id,
               first_name,
               last_name,
               status,
               type,
               rank() over (partition by membership_id
                                order by type desc) rnk
          FROM members )
 WHERE rnk = 1

will work for your sample data set. If you can have ties– that is, multiple rows with the same membership_id and the same maximum type— this query will return all those rows. If you only want to return one of the rows where there is a tie, you would either need to add additional criteria to the order by to ensure that all ties are broken or you would need to use the row_number function rather than rank which will arbitrarily break ties.