I am trying to automatically calculate a date field. What I would like to do is take a permit date and add 180 days to calculate an expiration date. I added a date field for the final calculation. I open the field calculator and write the expression. The expression verifies correctly but when I calculate the field I get errors. I tried several different calculations to see if any of them would work. Below is an example of a calc I did to extract a date. Again, the expression verified correctly but then this error popped up when I calculated the field.
From the error message, it appears you're using the extract function. This function, I believe, returns a number. If you are trying to assign this value to a date field, you'll get a field type mismatch of trying to calculate a number into a date field.
If your goal is to simply add 180 days to a date in a field and assign it to another field, you can form an expression like this:
[PermitDate] + 180
Under normal circumstances, this would yield a new date 180 days into the future. HOWEVER, THERE IS A BUG in AGOL with date addition, where it doesn't work. Subtraction, however works. So try this expression
[PermitDate] - -180
Where you subtract negative 180.
Mike