I am trying to add together string fields from the source database  that generally have numbers in. To do this I am converting to number using the ton umber() function. This works fine except when there is nothing in the field - a 'null' value. This does not hinder at the tonumber stage but when I come to add up the resultant numbers. can anybody help to convert the nulls to zeroes and so allow the addition.

 

Thanks

'use default values for nulls'