1. Built in Functions
Massaging the data

2. Functions SQL includes several built in functions
They all operate with the same pattern
SELECT FunctionName(Function arguments) FROM Tablename
Function can be nested inside of each other
SELECT MAX(SUM(Rate*Hours)

3. ALIASING
You can give a return column generated by a function a name or Alias
SELECT MAX(Rate) AS Highest
SELECT MAX(Rate) “Highest”

4. Most Common Functions
COUNT
MAX
MIN
SUM
AVG

5. Count COUNT counts the number of rows that meet a certain criteria.
It can be used on textual as well as numeric data
SELECT Count(*) FROM Orders
SELECT COUNT(CarrierCode) as ALASKA FROM ItinerayDetail WHERE CarrierCode=‘ALA’

6. MAX MAX returns the largest value in a column.
It can only be used with numeric fields and dates
SELECT MAX(Price) FROM Inventory

7. MIN Returns the lowest value in a column (again numeric or date)
SELECT MIN(RATE) FROM HourlyRate

8. SUM SUM Returns the total of numeric column
SELECT SUM(points) FROM Assignment WHERE StudentID=‘ ’

9. AVG AVG Returns the mean Average of a numeric column
SELECT AVG(heartrate) FROM Excercise

10. Aggregate Functions
All the functions that we have looked at are called aggregate functions
That means they work on groups of rows or values, rather than just one row or one value

11. GroupBy
If you include any columns in the SELECT of a query with an aggregate function you must GROUP BY those columns
SELECT StudentID, SUM(points) FROM Assignments GROUP BY StudentID

12. Having
Like the WHERE clause, but WHERE operates on individual records HAVING operates on Aggregrate (grouped) records
SELECT EmployeeID, COUNT(OrderID)
AS NumOrders
FROM ORDERS
GROUP BY EmployeeID
HAVING COUNT(OrderID)>100

13. Example SubQuery SELECT Orderid, unitprice FROM SaleDetail
WHERE Unitprice=
(SELECT MAX (UnitPrice) FROM SaleDetail