You can use isblank(). However, I recommend to enter another value (e.g., NULL) for unknown. The user can press Ctrl-zero) (or was it Ctrl-O?), or the programmer can define a default value of NULL.
See also: SET NULLDISPLAY.
Hilmar.
>User is entering 0 (because of someone else's form design) for unknown in statistical data fields, I'm trying to catch which fields are missing data. I'm assuming the obvious solution (since I can't change the coding) is to make the numeric fields accept null values, replace the fields with .null. when I Append Blank and then use isnull() as my criteria for checking for missing ones. I wanted to see if there are other alternatives that I'm not noticing as this solution feels a bit cludgy since I've got other fields that are not numeric types that I will be using the empty() criteria for. Am I making sense, and is this the best solution?
>
>Diana
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)