Filter by one column then count unique value in another column in SQL

I would like to filter data by column Base =1 and then count the number of unique values in another column 'Animal' in SQL, data:

    Animal  Base  Value   1   A       1     X       2   B       1     X      3   A       2     Y  4   A       3     V   

Expected output in this case is 2 from the first two rows.

https://stackoverflow.com/questions/67014493/filter-by-one-column-then-count-unique-value-in-another-column-in-sql April 09, 2021 at 10:59AM