Hiding null value from expression field in pivot/straight table

[#1]

So simply said, I have qlikview 10 and making a pivot table where there's an expression of day interval.

Such like this

Number Account interval (day2 - day1, 'DD')

011           mike      15

012            linda      23

013            tom        -

014            jean       -

And now I want to hide the fields (along with the number field, account field and many other field...) that has the -  or zero day intervals in that pivot table

Is this possible?

I've tried entering

if(interval (D2 - D1), 'DD' > 0, interval (D2-D1) , 'DD')

Doesnt work with '-', 0 or null()

Interval (D2-D1), 'DD' > 0

Doesnt work either

Sorta stuck over here...anybody knows how?

Thanks before

[Gysbert_Wassenaar]

If you want to use the 'DD' as a parameter for the interval function then you need include it in the parentheses of the interval function: interval (D2 - D1, 'DD')

And I don't understand the problem. Can you post a small qlikview document that explains the problem you're having?