SQL302 Intermediate SQL Workshop 2
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The document provides an overview of the SQL302 intermediate SQL programming course, including topics such as joins, set operations, and window functions. It includes details about the course resources, guidelines for naming conventions, and various SQL examples for different join types and operations. The content is designed to support SQL learning across different database systems while focusing on Microsoft SQL Server.
![More conventions
• Names can be surrounded with “ “ or [ ] as
in [order details].
• Some of the PowerPoint slides may have
this convention.
• Better practice is to use an underscore as in
order_details.
Bookstore SQL302 Module 2 8](https://image.slidesharecdn.com/sql302-s2-bk-121024143425-phpapp02/85/SQL302-Intermediate-SQL-Workshop-2-8-320.jpg)
![Unions
Select <column-list> from
<table1>
Union [ALL]
Select <same-columns> from
<table2>
Bookstore SQL302 Module 2 39](https://image.slidesharecdn.com/sql302-s2-bk-121024143425-phpapp02/85/SQL302-Intermediate-SQL-Workshop-2-39-320.jpg)
![Window Functions
Example: Show salary along with average for the
job_title and overall
Code:
use employeedb;
select soc_sec_no, name, salary
, SUM(salary) over(partition
by job_title_code) as [Job Code
Average]
, SUM(salary) over() as
[Average]
from employees;
Bookstore SQL302 Module 2 52](https://image.slidesharecdn.com/sql302-s2-bk-121024143425-phpapp02/85/SQL302-Intermediate-SQL-Workshop-2-52-320.jpg)
SQL302 Intermediate SQL Workshop 2
- 1. SQL302 Intermediate SQL Programming Based on SQL Clearly Explained by Jan Harrington and Microsoft SQL Server T- SQL Fundamentals by Itzki Ben-gan Workshop 2 – Joins, Set Operations, Window Functions Bookstore SQL302 Module 2 1
- 2. Note on SQL302 Slides • These slides were originally designed to support a single SQL course which was used for any of MS Access, MySQL, Oracle and SQL Server. • As such you may see here slides developed in any one of the above products. • We are in the process of migrating the Oracle, Access, and MySQL slides out into their own slide sets. The SQL302 slides will cover Microsoft SQL Server. Bookstore SQL302 Module 2 2
- 3. Warning! • Below are some table name changes to be aware of in doing queries. We have created synonyms so either name should work. New Name Old Name Orders Order_filled Order_Lines Orderlines Bookstore SQL302 Module 2 3
- 4. SQL302 Contact Information P.O. Box 6142 Laguna Niguel, CA 92607 949-489-1472 http://www.d2associates.com [email protected] Copyright 2001-2012All rights reserved. Bookstore SQL302 Module 2 4
- 5. SQL302 Resources • Bookstore database scripts found on box.net at http://tinyurl.com/SQLScripts • Slides can be viewed on SlideShare… http://www.slideshare.net/OCDatabases • Follow up questions? [email protected] Bookstore SQL302 Module 2 5
- 6. Relational Database with constraints (from text) Bookstore SQL302 Module 2 6
- 7. Sample Employees Database Bookstore2 & SQL204 Module 1 7 Employees
- 8. More conventions • Names can be surrounded with “ “ or [ ] as in [order details]. • Some of the PowerPoint slides may have this convention. • Better practice is to use an underscore as in order_details. Bookstore SQL302 Module 2 8
- 9. SQL302 SQL Programming Part 1 – Joins: Natural, Self and Outer Bookstore SQL302 Module 2 9
- 10. Joins • Inner (Covered in SQL202 course) • Natural Join • Self • Data Warehouse operators • Outer – Left – Right – Full • Cross • Theta • We will cover some of the more advanced or subtle aspects of joins in this class Bookstore SQL302 Module 2 10
- 11. Natural Joins • Table1 natural join table3 – automatically uses columns with same name • Table 1 natural join table2 using(<column- list> • Not yet available in SQL Server Bookstore SQL302 Module 2 11
- 12. Correlation Names (Table Aliases) • Can abbreviate references to tables • For example: Select e.name, j.payrange From employees as e Inner join job_information as j On e.jobcode = j.jobcode; Bookstore SQL302 Module 2 12
- 13. Self Joins • Implements a recursive relationship • Important in various applications – Parts lists/assemblies – HR – Etc. – Table joined to itself using correlation names Bookstore SQL302 Module 2 13
- 14. Self Joins SELECT e.*, m.name FROM employees AS e, employees AS m WHERE e.managerid = m.employeeid; Bookstore SQL302 Module 2 14
- 15. Bookstore SQL302 Module 2 15
- 16. Datawarehouse clauses • Two keywords that can be added to a grouped query – Rollup – Cube • Places additional summary rows in the result set • Result set is a true relational result set Bookstore SQL302 Module 2 16
- 17. Rollup • Example: calculate average salaries by job_title_code and manager Bookstore SQL302 Module 2 17
- 18. Rollup results Bookstore SQL302 Module 2 18
- 19. cube • Similar to rollup but computes summary rows in all dimensions Bookstore SQL302 Module 2 19
- 20. Cube results • Add a new set of rows which total by year Bookstore SQL302 Module 2 20
- 21. Bookstore SQL302 Module 2 21
- 22. Outer Joins • Left – selects all rows from the left or first table, even if no match exists in the other table – Widely used in commercial practice – Especially useful for reporting – Can be slower and interfere with optimizer • Right – same idea but all rows from right table • Full – all rows form both tables Bookstore SQL302 Module 2 22
- 23. Left Outer Join Basic SQL 92 Syntax: Select <column-list> From <table1> Left join <table2> On <join condition> Bookstore SQL302 Module 2 23
- 24. Left Outer Join • List all customers with their orders • Include customers with no orders as well Bookstore SQL302 Module 2 24
- 25. Left-Join Basic Example: SELECT customer_first_name, customer_street, order_numb, order_date from customers as c left join orders as o on c.customer_numb = o.customer_numb Bookstore SQL302 Module 2 25
- 26. Left Join with Results Bookstore SQL302 Module 2 26
- 27. Negative Left Join • List all the customers who have not placed any orders • This is an example of a query which finds unmatched records Bookstore SQL302 Module 2 27
- 28. Negative Left-Join (Unmatched) Basic Example: SELECT customer_first_name, customer_last_name, order_numb, order_date from customers as c left join orders as o on c.customer_numb = o.customer_numb Where order_numb is null; Bookstore SQL302 Module 2 28
- 29. Bookstore SQL302 Module 2 29
- 30. Left Join w/ Partial Match • List all customers along with any orders placed in 1999 • If they did not place 1999 orders we still want to include them in the printout Bookstore SQL302 Module 2 30
- 31. Left Join w/ Partial Match Example: SELECT customer_first_name, customer_last_name, order_numb, order_date from customers as c Left join (select customer_numb, order_numb, order_date From orders Where year(order_date) = 1999) as d on c.customer_numb = d.customer_numb; Bookstore SQL302 Module 2 31
- 32. Own Your Own • List all books and their order totals for 1999 • Show the book even if there were no orders placed in 1999 Bookstore SQL302 Module 2 32
- 33. Theta Joins • Theta joins involve inequalities in the matching conditions • Can be used for some interesting queries which do not involve the usual primary key to foreign key matchings Bookstore SQL302 Module 2 33
- 34. Theta join • Find all customers that live at the same address – Requires a self join of the customers table on address field Bookstore SQL302 Module 2 34
- 35. Theta join results • Can be further processed with a union query to consolidate names into a single list Bookstore SQL302 Module 2 35
- 36. SQL302 SQL Programming Part 3– Set Operations Bookstore SQL302 Module 2 36
- 37. Set Operations • More on unions • Intersect • Except Bookstore SQL302 Module 2 37
- 38. Unions • Combines two or more tables • Tables must be union compatible Bookstore SQL302 Module 2 38
- 39. Unions Select <column-list> from <table1> Union [ALL] Select <same-columns> from <table2> Bookstore SQL302 Module 2 39
- 40. Unions • Example: consolidate two columns into one column Bookstore SQL302 Module 2 40
- 41. Union consolidation result • Customers in same city Bookstore SQL302 Module 2 41
- 42. Unions • Example: add a total row to a query result • Code: use bookstore; select order_numb , sum(quantity) as "Quantity" , sum(cost_line)as "Total Cost" from orderlines group by order_numb union select NULL, sum(quantity), sum(cost_line) from orderlines; Bookstore SQL302 Module 2 42
- 43. unions • Example: add an element to a pick list Bookstore SQL302 Module 2 43
- 44. intersect • The intersect operator finds rows in common between two tables • Syntax Select <column-list> from <table1> intersect Select <same-columns> from <table2> Bookstore SQL302 Module 2 44
- 45. intersect • Example: find cities in common between sources and customers • Code select customer_city, customer_state, customer_zip from customers intersect select source_city, source_state, source_zip from sources; SQL302 Module 2 Bookstore 45
- 46. Except • Finds all rows from first table that are not found in the second table • Syntax: Select <column-list> from <table1> except Select <same-columns> from <table2> Bookstore SQL302 Module 2 46
- 47. except • Example: find sources that are not located in any of our customer’s cities • Code select source_city, source_state, source_zip from sources except select customer_city, customer_state, customer_zip from customers;SQL302 Module 2 Bookstore 47
- 48. SQL302 SQL Programming Part 4 – Window Functions Bookstore SQL302 Module 2 48
- 49. Aggregate Functions • Count • Sum • Min • Max • Avg • Often used in conjunction with grouping and window functions Bookstore SQL302 Module 2 49
- 50. Window Functions • Sort of like grouping, but aggregates can be taken along with straight columns in the select list • The function is applied over a window – Partition by column – Partition by () Bookstore SQL302 Module 2 50
- 51. Window Functions Basic syntax: Select …, window function(column) partition by <column> From <table> where <predicate> Bookstore SQL302 Module 2 51
- 52. Window Functions Example: Show salary along with average for the job_title and overall Code: use employeedb; select soc_sec_no, name, salary , SUM(salary) over(partition by job_title_code) as [Job Code Average] , SUM(salary) over() as [Average] from employees; Bookstore SQL302 Module 2 52
- 53. Exercise • List all customers and their orders – Name nicely formatted – With orders in the year of 1999 (do not use between, etc.) – Show total order quantities and amounts – Only include orders with more than three order lines Bookstore SQL302 Module 2 53
- 54. Notes Bookstore SQL302 Module 2 54
- 55. Notes Bookstore SQL302 Module 2 55