Figures - Chapter 2, Relational Algebra

 

 

 

JOIN Customer  Rep
    WHERE Customer.RepNum = Rep.RepNum
    GIVING  Temp  

If we only wanted to display the CustomerNum, CustomerName, and Rep LastName, then we use projection:  

PROJECT Temp
OVER (CustomerNum, CustomerName, LastName) GIVING  Answer

The Answer table is the same as the Temp table
without the columns RepNum and FirstName.