countd(customers) will include all the customers count.
when you apply this in filter if sum[sales] > 50 then 1 else 0 end then it will display >50 sales only. so customers those who bought >50 then it will count and give result.
First one shown Sales >100 and second one without filter
Thanks for your response. I wanted to clarify whether the customer name filer contains this criteria: if sum[sales] > 50 then 1 else 0 end