fieldName - the name of a field in the specified database file.
The field name must be in the form tablename::fieldname to specify a field that exists in a table different from the current table.
FieldComment("Customers"; "Phone Number") returns
“Customer's home telephone number” if it was entered as a comment for the Phone Number field.
FieldComment("Customers"; "Accounts::Current Balance") returns
“Customer's current balance” if it was entered as a comment for the Current Balance field in the Accounts table.