Filter duplicate rows based on a field

Question

I have several records (bills) that are basically duplicates of each other, except for one field, which represents the language that bill is in.

For example:

<

Answer 1

Probably the easiest way would be to use ROW_NUMBER and PARTITION BY

SELECT * FROM (
   SELECT b.*,
   ROW_NUMBER() OVER (PARTITION BY BillID ORDER BY Lang) as num
   FROM Bills b
   WHERE Account = 'abcd'
) tbl
WHERE num = 1