Show values when preceding value is null or zero

[#1]

Hi All,

I've got a set of data with 3 dims (as per below; period gets values from 1 to 6) and try to create an expresion that would show values when value from preceding period is null or is zero. Any idea how to create it?

Input

-------

Employee, Period, Amount

John, 1, 20

John, 3, 30

Mary, 1, 50

Mary, 2, 70

Output

---------

Employee, Period, Amount

John, 3, 30

Regards,

Przemek

[#2]

Any idea, please?

[llauses243]

Hi,

This is my offer, pls to see object attached

Good luck, Luis

[#4]

Hi Luis, thank you for your offer. It's a kind of way out but, as there as thousands of records, I'd need a chart showing only the values except for blanks + the values. Any idea on that?