I have a google sheets with two tabs in it. The first tab is data with the color and the name of the person who uses that color. Tab 2 is a summary tab where I would like to find the unique number of people using each color. That should fill in column 2 of the Summary tab. I included a list of expected values in column 3. The real document has 1000s of unique values in column 1 of the summary tab so it would be useful to get an equation that I can drag down.

Here is the trix: https://docs.google.com/spreadsheets/d/1hl1KRpyLoHsi_Q8MmIQJHvQDLJiwq6cdYd9YHd6ZzMY/edit?usp=sharing

CodePudding user response：

Try

=counta(unique(query(Data!A:B,"select B where A='"&A2&"' ")))