SQL SELECT Getting Data from the Database

Basic Format SELECT, FROM WHERE (=, >, LIKE, IN) ORDER BY ; SELECT LastName, FirstName, Phone, City FROM Customer WHERE City=‘Seattle’ ORDER BY LastName;

Key Words SELECT –every query that returns data starts with SELECT FROM –determines what table(s) WHERE –sets up the Criteria ORDER BY –sorts by the field(s) listed Note: SELECT * FROM Customer, the * means select all columns

AS, Aliasing The names of the columns may not always be the names you wish to use in a query result. You can use the AS keyword to alias it for the result SELECT LastName AS “Last Name”, FirstName AS “First Name” FROM Customer;

Calculated Fields SELECT 5 * 3 / 2; SELECT lastname + ‘, ‘ firstname AS “Customer Name”, Phone FROM Customer; SELECT OrderID, (ItemPrice * Quantity) AS “SubTotal” FROM OrderDetail WHERE OrderID=1223;

ORDER BY ORDER BY sorts by the selected field in an Ascending order by default. You can add the DESC keyword to change the sort order to Descending If you have multiple fields the leftmost is the primary sort, the next leftmost is the secondary sort etc. SELECT LastName, FirstName, City, phone FROM Customer ORDER BY City, LastName DESC; Note: the DESC only applies to the LastName field

WHERE CRITERIA You can use all the basic comparative operators OperatorDescription =Equals (number & character) >Greater than (number) <Less than <> !=Not equal

Criteria Number values are used without quotes Character (text) values are quoted with single ‘’ quotes Dates are quoted with single quotes except in Access where they put between pound # signs

Between You can use the BETWEEN keyword to look for values “between” to limiting values. The Between includes the ends SELECT OrderID, OrderDate FROM Order WHERE OrderDate BETWEEN #1/1/2007# AND #1/31/2007#;

AND OR NOT SELECT * FROM Customer WHERE State = ‘WA’ AND City = “Seattle” OR City = “Tacoma” AND NOT City = “Bellevue”

LIKE With the keyword LIKE in conjunction with wildcards will let you search for patterns in text fields The wild cards are % any string of characters _ any one character

LIKE Examples SELECT * FROM Customer WHERE LastName LIKE ‘Ch%’; SELECT * FROM Course WHERE CourseName LIKE ‘MIC12_’

Nulls You can search for Nulls with the key words IS NULL SELECT SectionNumber, StudentID, QuarterGrade FROM Section WHERE SectionID=‘2830’ AND QuarterGrade IS NULL