Hi all… Apologies in advance if this question is entered into the wrong forum. If so, please let me know where it would be best to ask this question. I am attempting to write an expression filter.

Essentially, what I would like to find are duplicate dollar amounts found in a variety of transactions. For example; A customer attempts a transaction for $512.44 using whatever credit card number they have.

However, the transaction may be declined multiple times before it gets approved. However, it may be they then attempt to use a different credit card number to get that amount of $512.44 approved.

I would like to write an expression filter that shows me duplicate transactions (2 or more) of a certain dollar amount like $512.44. I have attempted the following statement below but this does not appear to work:

case when COUNT(DISTINCT transaction_amount) >= 2 then 'suspicious transaction' else 'normal transaction' END

Any and all feedback would be greatly appreciated. Thank you all so much!