Example

Four columns are involved in the transformation. ZONE values also pass through to an output column called ZONE.

CUSTOMER	DIVISION	CITY	ZONE
`Acme`	`Toys`	`Boston`	`East`
`Acme`	`Toys`	`New York`	`East`
`Acme`	`Chemical`	`Raleigh`	`East`
`Acme`	`Chemical`	`St. Louis`	`Midwest`