count record with same fields

[MacSig]

Hello everyone.

How can I set the calculated value of field C to the number of records having field A equal to the value inserted to field A and field B equal to the value inserted to field B?

 

For instance with the following situation

 

record 1  =>  A = "house", B = "pay" 

record 2  =>  A = "house", B = "win" 

record 3  =>  A = "car", B = "pay" 

record 4  =>  A = "house", B = "pay" 

 

when I create a new record having  A = "house", B = "pay"  C should automatically be 2 (since record 1 and 4 have the same A, B.

 

Thanks

[comment]

Please don't ask abstract questions; more often than not, they lead to the wrong answers. Instead, explain what kind of objects your solution is tracking and what do you need it to do for you. I suspect that once you do that, it will turn out that the real problem here is structural.

[MacSig]

Thank for you reply.

Sorry for my question but I feel it is pretty concrete.

 

I have a table called gifts with 3 fields: kind - offer - count

Kind and offer may have value from a list

 

the kind list is "house car plane tricycle"

the offer list is "pay win lease" 

 

I wish to automatically calculate the value of count once selected both kind and offer.

Count should be the number of records having the same value of kind and offer.

 

 

I have tried to achieve so all the afternoon yesterday but even if this it seems to me a very simple thing I cannot figure out how to make it work.

 

Thanks everyone for helping solving my issue.

[comment]

I am afraid you haven't added anything new. I can answer your question as asked, but I have serious doubts if that's the best way to achieve [whatever this is supposed to achieve].

 

 

If you define a self-join relationship of your Gifts table as:

 

Gifts::Kind = Gifts 2::Kind

AND

Gifts::Offer = Gifts 2::Offer

 

you can then make Count a calculation field (Result is Number, Evaluate from the context of [Gifts]) =

Count ( Gifts 2::Kind )