Calculating total amount using two conditions.

[sun1171]

I am new to Access, in fact computers is not my field. I am a paramedic working with a health care institution.
I have made a db for billing purpose.There are to subforms linked by the Registration number.There are fixed charges for the Prod/Test.The number of units used keeps changing from patient to patient.
What I want is the total amount to be charged to patient should be done automatically in the Amount field in the Productdetail subform using the conditions Prod/Test and number of units.


Attached is the db.
Thanks.

[LillMcGill]

Be more specific. Prod/Test is a text field, how would anyone use that to generate an amount of anything? Maybe you need a Products table which includes the price per unit of each product.

[sun1171]

The charges to the Prod/Test varies on the basis of class (billing subform).
eg. for X-match charges in 'Economy' class is 880, for 'A' class is 1050, for 'AD' class is 1026.
I need to take into account the product,class and number of units to arrive at total amount.
I should have written this condition in the begining.