I need help with a validation formula in a SharePoint Text column where:
- column can be empty ( the default state when list is opened)
- column can be null (the state after a value is deleted)
- must be all numbers
- must be 8 digits long
My unsuccessful try:
=OR(ISBLANK(FCN]),(FCN]=""),""),AND(LEN([FCN])=8,ISNUMBER([FCN]+0)))
Thank you!