How to make sales tax amount conditional on date?
California sales tax changes by 1% today. My order entry program uses a variable "tax rate" set to ".0775". I need it to be ".0875" now, but I don't want the new value to recalculate everything in the past. I've tried to make the field "tax rate" be a calculation based on the field "Invoice Date", but I'm not getting the result I expect. I've been coasting for years on this program that I wrote literally in the last century. I no longer remember enough to get this to work. Can someone help?
I use this calculation field: If (Invoice Date < 04/01/2009; .0775; .0875)
But the tax rate stays .0875 no matter which date I enter into the field "Invoice Date".