The customer table of my SQL server database contains the following 3 column. There may be more than one customer having exactly the same last and first names while CustID is unique:
CustID, LastName, FirstName

Data currently showing in my "Customer Data" form are
CustID=671
LastName='Barnes'
FirstName='John'

What is the best SQL command to get the CustID of next (alphabetic order) customer?

Grateful if anybody can help.
KM