It's easy to create a query from a DB as below.
Let's say the above column name is ID, then you do count and count(distinct) for ID. It will show as this one.
It's wrong as NULL should not be counted in results. So could you please check and fix this issue? Thanks.
Please check the following response from PG:
"This is by design. We’ll provide a separate function to count discount values minus the BLANK in the future."Currently, please vote up this idea. Meanwhile, you can create the following measure to work around this issue.
Measure = CALCULATE(DISTINCTCOUNT('Yourtable'[ID]),FILTER(ALL('Yourtable'),'YourTable'[ID]<>BLANK()))
Okay and Thanks, Lydia.