The SELECT clause defines the list of attributes on the records produced by the statement.
Its syntax is as follows:
SELECT <expression> AS <attribute key>[, <expression> AS <key>]*For example:
SELECT Sum(Amount) AS TotalSales
The attribute definitions can refer to previously defined attributes, as shown in the following example:
SELECT Sum(Amount) AS TotalSales, TotalSales / 4 AS QuarterAvg