Hi, I have a table below which i need to count the number of unique people who own the same brand of car as Peter. The formula should return 3, 2 from toyota(Paul and David) and 1 from Honda(Ken), it should count David from Nissan as it's a duplicate. Anyone can help to solve this? Thanks
Car | Year | Name |
Toyota | 1999 | Peter |
Toyota | 2000 | Paul |
Toyota | 1998 | David |
Mazda | 1997 | Michael |
Honda | 1997 | Peter |
Honda | 1998 | Ken |
Nissan | 1999 | Peter |
Nissan | 1998 | David |
Ford | 1999 | Peter |