Including Null Values

[#1]

I have the following data set:

U-Date            Amount

7/8/2013         2280.00

-                      2227.50

10/24/2013     2475.00

-                      2475.00

6/24/2008        2475.00

I want to sum the amounts of U-Date greater than 7/1/2013 and include the - values.  I have tried different formulas and it is not working.  Any suggestions?

David

[Anonymous]

If it is in a text box, it could be:

sum(if("U-Date"> date('7/1/2013') OR len(trim("U-Date"))=0, Amount))

[maxgro]

or perhaps

=sum(if ( alt([U-Date],'12/31/2099') > date('7/1/2013'), Amount))