Help in developing a query with possible nul values

[Viggen66]

Dear all

I have already posted another thread, but now I need your help in developing a query.

I'm developing a database to make control of the inflow of invoices entering the accounting department, but as the size of the database increases, when I want to query for the invoices of a particular vendor, I will get an enormous list of all the historic data of that particular vendor, so the solution was to make access filter the invoices by a certain number of days, in this expression.

>Date()-[Forms]![Vendor]![Dates Due]

But the main problem is that [Dates Due] is an input from a text box, and for the query to work I need to always insert a number, or else I will get a nul result.



Is there a way to fix this, with the use of the iff, like for instance

If ([Dates Due]=Nothing then ignore this parameter, [Dates Due] equals a number, then insert this number in the query), I’m very used on using Excel, and I don’t know how to do this in Access.

Thanks

[Viggen66]

I have already fixed this problem

I have made a combobox, where I can chose between 30 60 90 120 180 and 365 days, and the default value for that is 30 days.

So the problem of not entering data is solved.