Joins an array of strings together into a single string using a separator.
string JOIN(string separator, params string values)
JOIN("|", "Phil", "David", "William")
Will return "Phil|David|William".
Using a customer list with the columns CustFirstname and CustSurname you can join them to get the customer full name in the format surname, first name. In this example we will use CustFirstname = John and CustSurname = Smith:
JOIN(", ", CustSurname, CustFirstname)
Which will return Smith, John.