1. Getting to Know SQL

2. © Jim Hope 2004 All Rights Reserved Data Manipulation SELECT statement INSERT INTO statement UPDATE statement DELETE statement UNION operation

3. © Jim Hope 2004 All Rights Reserved Data Definition CREATE TABLE statement CREATE INDEX statement ALTER TABLE statement CONSTRAINT clause DROP statement SELECT... INTO statement

4. © Jim Hope 2004 All Rights Reserved 1 SELECT SELECT * FROM People ; Means: Select all the fields (*) for all rows from the table called People

5. © Jim Hope 2004 All Rights Reserved 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 2004 All Rights Reserved 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 2004 All Rights Reserved 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 2004 All Rights Reserved 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 2004 All Rights Reserved 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 2004 All Rights Reserved 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 2004 All Rights Reserved 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 rows with duplicate Scores presented alphabetically by player

12. © Jim Hope 2004 All Rights Reserved 5a Putting things together SELECT LastName, FirstName, Score FROM People WHERE Score >=290 or Score <=100 ORDER BY Score DESC What is this doing?

13. © Jim Hope 2004 All Rights Reserved 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

14. © Jim Hope 2004 All Rights Reserved 5c Putting more things together SELECT LastName, FirstName, Score, City FROM People WHERE (Score >=290 or Score "Surrey" and City <> "Burnaby" ORDER BY Score DESC What is this doing, and what else would you add?

15. © Jim Hope 2004 All Rights Reserved 5d Putting more things together SELECT LastName, FirstName, Score, City FROM People WHERE (Score >=290 and City <> "Surrey") or (Score "New York") ORDER BY Score DESC What is this doing

16. © Jim Hope 2004 All Rights Reserved 5e Scope 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”

17. © Jim Hope 2004 All Rights Reserved 5f Whatnot SELECT LastName, FirstName, Score FROM People WHERE LastName NOT IN ("Bundy", "Simpson", "Petrie"); Try this one

18. © Jim Hope 2004 All Rights Reserved 6a Counting SELECT count(*) FROM People

19. © Jim Hope 2004 All Rights Reserved 6b Counting SELECT count(*) FROM People WHERE Score <100

20. © Jim Hope 2004 All Rights Reserved 6b Counting SELECT count(*) FROM People WHERE Score <100

21. © Jim Hope 2004 All Rights Reserved 7 Wildcards SELECT LastName, FirstName FROM People WHERE LastName like 'b*' or MS Access (WHERE LastName like 'b*')

22. © Jim Hope 2004 All Rights Reserved 8a You can do math? SELECT LastName, FirstName, Score, Score +10 as BigScore FROM People ORDER BY Score DESC

23. © Jim Hope 2004 All Rights Reserved 9a Create an Alias with CONCAT SELECT CONCAT(LastName,", ",FirstName) AS FullName FROM PEOPLE ORDER BY LastName, FirstName Question: who is [Null]? --- alternate form (MS Access) SELECT LastName +", " + FirstName as FullName FROM People

24. © Jim Hope 2004 All Rights Reserved 9b Who was NULL? SELECT LastName, FirstName, CONCAT(LastName,", ",FirstName) AS FullName FROM PEOPLE ORDER BY LastName, FirstName This answers the question – who is [NULL] in the previous example

25. © Jim Hope 2004 All Rights Reserved 10a Max & Min SELECT MAX (Score) FROM People SELECT MIN (Score) FROM People

26. © Jim Hope 2004 All Rights Reserved 10b Simple Stats and Aliases SELECT MIN(Score) as `Lowest Score`, ROUND(AVG(Score),2) as Average, MAX(Score) as `Highest Score`, ROUND(STD(Score),2) as `Standard Deviation` FROM People

27. © Jim Hope 2004 All Rights Reserved 10c Limiting Rows Returned SELECT LastName, FirstName, Score FROM People ORDER BY Score DESC LIMIT 1 Who are we missing here?

28. © Jim Hope 2004 All Rights Reserved 10c Max again SELECT LastName, FirstName, Score FROM People WHERE Score = (SELECT MAX(Score) FROM People); This is a Subquery Version 4.1 Alpha

29. © Jim Hope 2004 All Rights Reserved 11 Keeping things DISTINCT Try This… SELECT City FROM People Then Try SELECT DISTINCT City FROM People

30. © Jim Hope 2004 All Rights Reserved 12a More than one table Try SELECT `Team Name` FROM Team Then Try SELECT `Team Name`, LastName, FirstName FROM Team, People This creates a Cartesian Product!

31. © Jim Hope 2004 All Rights Reserved 12b More than one table SELECT `Team Name`, LastName, FirstName FROM Team, People WHERE Team.Team=People.Team ORDER BY `Team Name`, LastName, FirstName

32. © Jim Hope 2004 All Rights Reserved 12c Using Join SELECT `Team Name`, LastName, FirstName FROM Team INNER JOIN People ON Team.Team=People.Team ORDER BY `Team Name`, LastName, FirstName Last two lines no longer required FROM People, Team WHERE People.Team=Team.Team

33. © Jim Hope 2004 All Rights Reserved 12c Using Join SELECT LastName, FirstName, Score, `Show Name` FROM People INNER JOIN `Show` ON People.Show = Show.Show ;

34. © Jim Hope 2004 All Rights Reserved 12d Using Left Join SELECT LastName, FirstName, Score, `Show Name` FROM People Left JOIN `Show` ON People.Show = Show.Show ;

35. © Jim Hope 2004 All Rights Reserved 12e Using Right Join SELECT LastName, FirstName, Score, `Show Name` FROM People Right JOIN `Show` ON People.Show = Show.Show ;

36. © Jim Hope 2004 All Rights Reserved 13a Group By – putting it together SELECT `Team Name`, ROUND(AVG(Score),2) AS `Average` FROM People,Team WHERE People.Team=Team.Team GROUP BY Team.`Team Name`

37. © Jim Hope 2004 All Rights Reserved 13b Inner Join and Group By SELECT `Team Name`, ROUND(AVG(Score),2) AS `Average` FROM Team INNER JOIN People ON People.Team=Team.Team GROUP BY Team.`Team Name

38. © Jim Hope 2004 All Rights Reserved 14 SELECT INTO (new table) SELECT Team.`Team Name`, AVG(Score) AS `Average` INTO TeamSummary FROM People INNER JOIN Team ON People.Team = Team.Team GROUP BY Team.`Team Name` Sorry – you don’t have permissions to do this on the netpub instance of MySQL

39. © Jim Hope 2004 All Rights Reserved 16 SELECT with IF SELECT LastName, IF(FirstName IS NULL, Description, FirstName) as Salutation, Score FROM People, Titles WHERE People.t = Titles.Titles

40. © Jim Hope 2004 All Rights Reserved 16 SELECT and GROUP BY SELECT `Team Name`, avg(Score) as AvgScore FROM People, Team WHERE People.Team = Team.Team GROUP BY `Team Name`

41. © Jim Hope 2004 All Rights Reserved That’s enough of that