Extraction, Transformation, and Loading - Data Warehouse Systems: Design and Implementation - page 301

Fig. 8.23 Load of the Customer dimension table
matching values of City and Country in a lookup table defined by the following
SQL query:
SELECT CityKey, CityName, CountryName
FROM City C JOIN Country T ON C.CountryKey = T.CountryKey
Then, we send the obtained records to a union task in order to load them in
the data warehouse.