I give an example. The table Family has the following records:

RECNO     NAME               DATE OF BIRTH     ADDRESS
1         father_a           Oldest            a_city     <- Select
2         mother_a                             a_city
3         son_a                                a_city
4         daughter_b                           b_city
5         grandmother_b      Oldest            b_city     <- Select
6         mother_c           Oldest            c_city     <- Select

I need to send ONLY ONE letter to every family that the member is the oldest, and all members of a family have the same address. So RECNO 1, 5 & 6 are selected.

How to write the SQL command to select these records?

Thanks in advance.