Zend certified PHP/Magento developer

How to write multiple IF conditions using table arguments in excel

enter image description hereUsing a table reference arguments, how to write this formula to check multiple IF conditions and perform a calculation?

Check below Four column conditions and then perform calculation Date1-Date2

In excel, my table name is: Details

Column 1: values
type In (new, old, contract)

Column 2:
Letter : Yes

Column 3 :
Business: Hospital

Column 4 :
Isnotblank(Date1)

perform calculation Date1-Date2

Else “”

I am not sure how to combine all these conditions in a formula. Shows in the image attachment