1. Getting to Know SQL

2. © Jim Hope 2002 All Rights Reserved Data Manipulation SELECT statement INSERT INTO statement UPDATE statement DELETE statement TRANSFORM statement UNION operation

3. © Jim Hope 2002 All Rights Reserved Data Definition CREATE TABLE statement CREATE INDEX statement ALTER TABLE statement CONSTRAINT clause DROP statement SELECT... INTO statement

4. © Jim Hope 2002 All Rights Reserved Example 1 SELECT * FROM people ; Means: Select all the fields (*) for all rows from the table called people

5. © Jim Hope 2002 All Rights Reserved Example 2 Specify Fields SELECT lastname, firstname FROM people ; Means: Select the fields (lastname and firstname) for all rows from the table called people

6. © Jim Hope 2002 All Rights Reserved Example 3a Setting the Scope SELECT lastname, firstname, score FROM people WHERE score >=250 Means: Select the fields (lastname, firstname, score) for only rows where the score is greater than or equal to 250

7. © Jim Hope 2002 All Rights Reserved Example 3b Setting the Scope SELECT lastname, firstname, score FROM people WHERE score >=250 OR score <=100 Means: Select the fields (lastname and firstname, score) for only rows where the score is greater than or equal to 250 or the score is less than or equal to 100

8. © Jim Hope 2002 All Rights Reserved Example 4a Setting the Order SELECT lastname, firstname FROM people ORDER BY lastname ; Means: Select the fields (lastname and firstname) for all rows from the table called people, in alphabetical (ascending) order by the values in the lastname field.

9. © Jim Hope 2002 All Rights Reserved Example 4b Setting the Order SELECT lastname, firstname FROM people ORDER BY lastname, firstname ; Means: Select the fields (lastname and firstname) for all rows from the table called people, in alphabetical (ascending) order by the values in the lastname field. If there are duplicates – use the firstname (ascending)

10. © Jim Hope 2002 All Rights Reserved Example 4c Setting the Order SELECT lastname, firstname, score FROM people ORDER BY score DESC, lastname, firstname; Means: Select the fields (lastname and firstname) for all rows from the table called people, in (descending) order by the values in the score field.

11. © Jim Hope 2002 All Rights Reserved Example 4d Setting the Order – you try SELECT lastname, firstname, score FROM people ORDER BY score DESC What would you do if you wanted to see duplicate scores presented alphabetically

12. © Jim Hope 2002 All Rights Reserved Example 5a Putting things together SELECT lastname, firstname, score, FROM people WHERE score >=290 or score <=100 ORDER BY score DESC What is this doing, and what else would you add?

13. © Jim Hope 2002 All Rights Reserved Example 5b Putting more things together SELECT lastname, firstname, score,city FROM people WHERE (score >=290 or score "Surrey" ORDER BY score DESC What is this doing, and what else would you add?

14. © Jim Hope 2002 All Rights Reserved Example 5c More Scoping with IN SELECT lastname, firstname, score FROM people WHERE lastname IN ("Bundy", "Simpson", "Petrie"); (much better than… WHERE lastname = “Bundy” OR lastname = “Simpson” OR lastname = “Petrie”

15. © Jim Hope 2002 All Rights Reserved Example 5d Whatnot SELECT lastname, firstname, score FROM people WHERE lastname NOT IN ("Bundy", "Simpson", "Petrie"); Try this one

16. © Jim Hope 2002 All Rights Reserved Example 6a Counting SELECT count(*) FROM people

17. © Jim Hope 2002 All Rights Reserved Example 6b Counting SELECT count(*) FROM people WHERE score <100

18. © Jim Hope 2002 All Rights Reserved Example 7 Wildcards SELECT lastname, firstname FROM people WHERE lastname like 'b*‘ (WHERE lastname like 'b%‘)

19. © Jim Hope 2002 All Rights Reserved Example 8 You can do math? SELECT lastname, firstname, score, score +10 as bigscore FROM people ORDER BY score DESC

20. © Jim Hope 2002 All Rights Reserved Example 9 Create an Alias SELECT lastname +", " + firstname as fullname FROM people ORDER BY lastname, firstname

21. © Jim Hope 2002 All Rights Reserved Example 10a Max & Min SELECT max (score) FROM people SELECT min (score) FROM people

22. © Jim Hope 2002 All Rights Reserved Example 10b Max again SELECT lastname, firstname, score FROM people WHERE score = (SELECT max(score) FROM people); This is a subquery

23. © Jim Hope 2002 All Rights Reserved Example 11 Keeping things DISTINCT SELECT DISTINCT city FROM people;

24. © Jim Hope 2002 All Rights Reserved Example 12a More than one table SELECT lastname, firstname, score, [show name] FROM people, show ; This creates a Cartesian Product

25. © Jim Hope 2002 All Rights Reserved Example 12b More than one table SELECT lastname, firstname, score, [show name] FROM people, show WHERE people.show=show.show ;

26. © Jim Hope 2002 All Rights Reserved Example 12c Using Join SELECT lastname, firstname, score, [show name] FROM People INNER JOIN Show ON people.show = show.show ; FROM people, show WHERE people.show=show.show ;

27. © Jim Hope 2002 All Rights Reserved Example 12c Using Join SELECT lastname, firstname, score, [show name] FROM People INNER JOIN Show ON people.show = show.show ;

28. © Jim Hope 2002 All Rights Reserved Example 12d Using Left Join SELECT lastname, firstname, score, [show name] FROM People Left JOIN Show ON people.show = show.show ;

29. © Jim Hope 2002 All Rights Reserved Example 12e Using Right Join SELECT lastname, firstname, score, [show name] FROM People Right JOIN Show ON people.show = show.show ;

30. © Jim Hope 2002 All Rights Reserved That’s enough of that