SQL & PL/SQL :: Latest Date (or Max Date) For Consumers

The oracle table has the following fields,

A_ID, B_ID, CONSUMER_ID, U_DATE, ACTIVE_FLAG.

1 0 111 Jan-02-07 N
1 1 111 Feb-02-07 N
1 2 111 Mar-02-07 Y
1 3 111 Apr-02-07 Y
1 4 111 May-02-07 Y
1 1 222 Feb-06-07 N
1 1 222 Mar-06-07 N
1 1 222 Jun-06-07 Y
1 1 222 Jul-06-07 Y

The table has incorrect data. meaning for each consumer_id we want the ACTIVE_FLAG to be 'Y' only for it's latest record and the rest to be inactive. i.e. we want the data as follows:

A_ID, B_ID, CONSUMER_ID, U_DATE, ACTIVE_FLAG.

A_ID, B_ID, CONSUMER_ID, U_DATE, ACTIVE_FLAG.

1 0 111 Jan-02-07 N
1 1 111 Feb-02-07 N
1 2 111 Mar-02-07 N
1 3 111 Apr-02-07 N
1 4 111 May-02-07 Y
1 1 222 Feb-06-07 N
1 1 222 Mar-06-07 N
1 1 222 Jun-06-07 N
1 1 222 Jul-06-07 Y