UTEP Oracle 9i
UTEP Oracle 10g Notes

Projection

Understanding the concept:

While restriction takes a horizontal slice of a recordset, projection takes a vertical slice; it returns only a subset of the fields in the original recordset.

SQL performs this simple operation using the <fieldList> section of the SELECT statement by only including the fields that you list. For example, you could use the following statement to create an employee phone list:

SELECT LastName, FirstName, Extension 

FROM Employees

ORDER BY LastName, FirstName;

Remember that the ORDER BY clause does just that, it sorts the data; in this case, the list will be sorted alphabetically by the LastName field and then by the FirstName field.