Subtract 2 rows in a query function in Google Sheets

Question

My dataset comes from a Google formular.
I will have 2 different entries with the same names.

The data input in the different columns will increase.

What I want to do now is automatically subtract the data from the same columns between the 2 rows with the same names in column A.

I only could get the sum function to work like that, but I need the minus function.

=query(A:B, "select A, sum(B) group by A")

This one works for the sum, but I need to subtract the first entry from the 2nd one.

I would really appreciate some help.
The query function is needed, because that's not the only thing I want to do.

Answer 1

Based solely on what you've shown in your post (which is all we have to go on), you will only ever have two instances of any given name: one with a lower number for the name and one with a higher number for the name.

Give that condition:

=query(A:B, "select A, max(B)-min(B) where A is not null group by A label max(B)-min(B) ''")

I've written this in the style of the formula you originally presented, rather than in my own style, so that it will be most understandable to you.

Answer 2

thank you very much, that helps! I will even have more than 2 entries of the same name later on, would it maybe be possible to select the 2 instances I use for the substraction based on dates when the entry from the google form was made?