Crystal Report --Missing number

Question

I have a list of numbers and I want to somehow know if there is a number missing.

Answer 1

Not a lot of information to go on, but going by two definitions of "missing", consider using Crystal's conditional formatting:

a. If "missing" means empty or null, check for that, and flag the outputted field with color and/or replacement text.

b. If "missing" means a number in a series isn't there, you'll have to create a running total or similar to fit the series, then compare that to what your data is returning. When they don't match up, that's when you flag the missing number.

Answer 2

Assuming this is a consecutive list of numbers (ie 1,2,3,4, etc) and you're looking for gaps, add a formula like this (Crystal Syntax) :

If Not (PreviousIsNull({Table.NumberField})) Then
    (Previous({Table.NumberField}) <> {Table.NumberField} - 1)
Else
    False

This will return True if the current row is not one more than the previous row.

Otherwise, one of David's solutions is more suitable.