I've been tasked with merging our internal DVD, classical music and
general music databases (currently stored in 3 separate MSSQL
databases) into one DB.

In the new design title information for all 3 types is stored in the
PRODUCT table and release information per title is stored in the
PRODUCT_DETAIL table. Classical products have more information at the
title level, so that is stored in the CLASSICAL_PRODUCT table (which
is 1:1 with PRODUCT).

I need a way of being able to select from the PRODUCT table based on
type, and rather than adding a "type" column to PRODUCT (e.g. 1 = DVD,
2 = general music, 3 = classical) I thought considering I already have
a CLASSICAL_PRODUCT table why don't I just add a DVD_PRODUCT and
MUSIC_PRODUCT table that only list their product ID's so I can select
based on type but using a join instead.

Is there any advantage doing it one way over the other?

TIA