How to do a specific excel sum only when certain cells are filled

[Debjanes]

Hi all. Wondering if anyone can help me? I know how to do basic sums in excel but having trouble with one specifically and google doesn't seem to help.

For example I want a sum that does the following in H2
=sum(G2-A2)

HOWEVER I only want it to give me a value when there is a value in the G2 box. Both G2 A2 are dates and i want to know the number of days between those two dates. So if i set the answer box to number rather than date it works if there is a value in G2. If there isn't a date in G2 it gives me a massive minus figure as it is trying to take a date from a blank. Hope that makes sense? I only want the calculation in each H row to have a figure in if the G column isn't blank.

Would really appreciate your help as it would make my day so much easier.

 

[njimack]

=if(g2,g2-a2,0)

 

[Debjanes]

Thank you. Is there anyway to not have '0's in the boxes where there was no value in the matching part though? As this messes up my average sums at the bottom of that column. Could do with there being nothing in those cells instead of a ). Sorry to be a pain. Thank you so much for helping.

 

[Fluff]

Just replace the 0 with ""