1. SQL
Chapters 6 & 7

2. Sql queries

3. Querying Data Retrieving Data Sorting Data Filtering Retrieved Data
Combining filters
Wildcard filters
Creating Calculated Fields
Using Functions
Grouping Data
Filtering groups
Accessing Data from Multiple Tables
Subqueries
Joins
Creating Data Views

4. Retrieving data

5. Querying Tables Basic Format: Rules: SELECT column(s) FROM table
[WHERE condition(s)];
Rules:
SELECT must be first clause
FROM must be second clause
Case does not matter (in SQL Server)
Table/column names must be spelled as in the database
Use double quotes for object names, single quotes for literal strings

6. Selecting all rows, specific columns
SELECT column1[, column2, column3,…,columnX]
FROM table;
List all customer IDs on orders
SELECT customer_ID
FROM order_t;

7. Selecting All Rows, all columns
FROM table;
Display information about all orders
FROM order_t;

8. Selecting Unique Rows SELECT DISTINCT column(s) FROM table;
List all customers who've placed orders.
SELECT DISTINCT Customer_ID FROM Order_t;

9. Sorting data

10. Sorting Results ORDER BY
Orders results in ASC or DESC order of column(s)
List customer names and addresses
in descending order of customer's name.
SELECT Customer_name, Customer_address
FROM Customer_t
ORDER BY Customer_name DESC;
List product numbers, descriptions, and quantities on hand for all products. Show products with highest quantities first, and then in alphabetical order of product description.
SELECT Product_id,
product_description, qty_on_hand
FROM Product_t
ORDER BY qty_on_hand DESC,
product_description ASC;

11. filtering data

12. Search Conditions For retrieving specific rows: SELECT column(s)
Comparison Operators
Boolean Operators
Special Operators
Calculated Fields (Expressions)
SELECT column(s)
FROM table
WHERE <search condition(s)>;

13. Comparison Operators, con't...
= equal to
> greater than
< less than
>= greater than or equal to
<= less than or equal to
<> not equal to

14. Comparison Operators, cont…
Show order IDs and dates of all orders placed by customer 1.
SELECT Order_ID, Order_Date
FROM Order_t
WHERE Customer_ID = 1;
Show the time that order #1002 was placed.
SELECT Order_id,
CONVERT(varchar(8), Order_Date, 8) AS "Order Time"
FROM Order_t
WHERE Order_id = 1002;

15. Boolean Operators Boolean Operators
AND all search conditions must be met
OR any search condition must be met
NOT a search condition must not be met
Show orders placed by customer 1 with order ID(s) higher than 1005.
SELECT *
FROM Order_t
WHERE Customer_ID = 1
AND Order_ID > 1005;

16. Order of evaluation NOT, AND, OR
Use parentheses to ensure desired ordering
Show orders placed by CUSTOMERS EXCEPT customer 1, and with order ID(s) higher than 1007
Show orders placed by customers except customer 1, that have EITHER an order ID higher than 1007 OR an order date on the 24TH of the month

17. Special Operators
Shortcuts IN
BETWEEN
Wildcard matching
LIKE
NULL
TOP

18. Special Operators, cont…IN
Find dates that customers 1, 3, & 5 placed orders.
SELECT Customer_ID, Order_Date
FROM Order_t
WHERE Customer_ID IN (1,3,5);
BETWEEN
Find dates of orders placed by customers 1 thru 5.
WHERE Customer_ID BETWEEN
1 AND 5;

19. Special Operators, cont…
LIKE
Show customers with 'furn' in their names.
SELECT Customer_Name
FROM Customer_t
WHERE Customer_Name LIKE '%furn%';
Show customers with 'furn' + 5 characters in their names.
WHERE Customer_Name LIKE '%furn_____';

20. Special Operators, cont…
Null
unknown
not applicable
List customers who do not have an address listed.
SELECT Customer_ID, Customer_Name
FROM Customer_t
WHERE Customer_address IS NULL;
Beware…
SELECT Customer_Name
FROM Customer_t
WHERE Customer_address = NULL;

21. Special operators, cont…
TOP n
Displays first N rows of query results
Display the first 3 orders…
SELECT TOP 3 *
FROM order_t;
FROM order_t
ORDER BY order_date;
 In the table???
 That we ever received???

22. Special operators, cont…
TOP n WITH TIES
Displays query result rows that have tie/duplicate values
Therefore may return more than N rows
ORDER BY is required
Which 2 products have the highest inventory?
SELECT TOP 2 product_id, product_description, qty_on_hand
FROM product_t
ORDER BY qty_on_hand DESC;
Which products have the 2 highest inventory levels?
SELECT TOP 2 WITH TIES product_id, product_description, qty_on_hand

23. Calculated fields, expressions

24. Using Column Aliasing Assign friendly names to existing columns
Assign names to derived columns
Only exists for duration of query
SELECT column_name AS "alias_name" [, ….]
FROM table;
Show order information for customers 1, 3, and 4. Label the order dates "Date of Order".
SELECT Order_ID, Order_Date AS "Date of Order", customer_id
FROM Order_t
WHERE customer_id IN (1, 3, 4)
ORDER BY customer_id;

25. Using table aliasing Assign friendly (shortened) names to tables
Allows same table to be referenced multiple times in a query
Only exists for duration of query
SELECT column_name(s)[, ….]
FROM table table_alias;
List descriptions of all products with any kind of “natural” finish.
SELECT Product_description
FROM Product_t P
WHERE P.product_finish LIKE 'Natural%';

26. Expressions Manipulating column values in a query Effect is Temporary
Show the effect of increasing product prices by 10% for those products that are currently priced under $300.
SELECT Product_ID, Standard_Price AS "Old Price", Standard_Price*1.1 AS "New Price"
FROM Product_t
WHERE Standard_Price < 300;

27. Concatenating values Connecting text values together
Show the name, full address (street, city, state, zip) and number of orders placed by each customer in Florida.
SELECT customer_name,
customer_address + ', ' + city + ', ' + state + ', ' +
postal_code AS "address", orders_placed
FROM customer_t
WHERE state = 'fl';

28. Sql server cast function
Converts data from one datatype to another
Use for all other datatype conversions
CAST ( value AS target_data_type [ ( length ) ] )
Examples:
SELECT 'The list price is: ' + CAST(standard_price AS
varchar) FROM product_t;
Print 'old zip: ' + AS varchar)…;

29. functions

30. Functions Display, convert, manipulate values Aggregate Scalar Text
Date/Time
Year, Month, Day …
Mathematical
Floor, Ceiling, Round ….
System
System_User
GetDate()
Aggregate
COUNT
MIN
MAX
SUM
AVG

31. scalar functions

32. DATES Work with dates in ways other than mm/dd/yy
Can also use CONVERT function to do this
General Information on SQL Server Date functions:
Examples of using Date functions
Function
Description
GETDATE()
Returns the current date and time
DATEPART()
Returns a single part of a date/time
DATEADD()
Adds or subtracts a specified time interval from a date
DATEDIFF()
Returns the time between two dates or times
CONVERT()
Displays date/time data in different formats
DAY(), MONTH(), YEAR()
Returns the day, month, or year portion of a date

33. Dates, cont… Show the year customer 1 last placed an order.
SELECT TOP 1 YEAR(order_date) AS "Year Last Ordered"
FROM order_t
WHERE customer_id = 1
ORDER BY order_date DESC;
Show the different months that orders were placed.
SELECT DISTINCT MONTH(order_date)
FROM order_t;
SELECT DISTINCT DATENAME(month, order_date) AS "Month"

34. Dates, cont…
How many months have elapsed between our order dates and today?
SELECT DATEDIFF(MONTH, order_date, GETDATE())
FROM order_t;
* syntax is DATEDIFF(datepart, start_date, end_date)
** see for examples of how to subtract other date parts such as times
Show how old, in years, our orders are. Show results in descending order of age.
SELECT order_id, YEAR(getdate()) - YEAR(order_date) AS "Order Age in Years"
FROM order_t
ORDER BY "Order Age in Years" DESC;

35. numeric Performs mathematical functions
Show the effects of decreasing product prices by 3.5%.
SELECT product_id, standard_price, standard_price*.965
FROM product_t;
SELECT product_id, standard_price, ROUND(standard_price*.965, 2)
SELECT product_id, standard_price, FLOOR(standard_price*.965)

36. SYSTEM Retrieves information maintained by SQL Server
Who is the user currently logged on?
SELECT SYSTEM_USER;
What is today's date?
SELECT GETDATE();
What orders were placed in the current month of any year?
SELECT *
FROM order_t
WHERE MONTH(order_date) = MONTH(GETDATE());

37. Aggregate functions

38. Aggregate Functions
Produce aggregated data
COUNT
MIN
MAX
SUM
AVG

39. Count Counts number of rows/values retrieved from query
How many orders are there?
SELECT COUNT(*) FROM Order_t;
Show how many orders were placed after Nov 1st 2000.
SELECT COUNT(*)
FROM Order_t
WHERE Order_Date > '01-NOV-00';
How many orders have customer IDs?
SELECT COUNT (Customer_ID) FROM Order_t;
How many different customers have placed orders?
SELECT COUNT (DISTINCT Customer_ID)
FROM Order_t;

40. Min and Max Finds minimum/maximum value of attribute
Find date of most recent order.
SELECT MAX(Order_Date) FROM Order_t;
Show the earliest year that an order was ever placed.
SELECT MIN (YEAR(Order_Date))
FROM Order_t;
Show the date that customer 1 first placed an order.
SELECT MIN(Order_Date)
FROM Order_t
WHERE Customer_ID = 1;

41. Sum and Avg SELECT SUM(qty_on_hand) FROM Product_t;
SUM (totals values for specific attribute)
How many products are in inventory?
SELECT SUM(qty_on_hand) FROM Product_t;
AVG (finds average value of an attribute)
What's the average price of our products?
SELECT AVG(Standard_Price) FROM Product_t;
List the average product price and lowest product quantity on hand of our products.
SELECT AVG(Standard_Price),MIN(qty_on_hand) FROM Product_t;

42. Grouping data

43. Categorizing Results GROUP BY
groups output according to an attribute
can perform operations on groups of rows
List the average product price and lowest product quantity on hand for each product finish we offer.
SELECT Product_finish, AVG(Standard_Price), MIN(qty_on_hand)
FROM Product_t;
SELECT Product_finish,AVG(Standard_Price),MIN(qty_on_hand)
FROM Product_t
GROUP BY Product_finish;

44. More on Group By’s… How many customers are there in each state?
SELECT COUNT(customer_id)
FROM customer_t GROUP BY state;
SELECT COUNT(customer_id), state
How many customers are in each postal_code area of each state?
SELECT COUNT(customer_id), state, postal_code
FROM customer_t
GROUP BY state;
GROUP BY state, postal_code;

45. Categorizing Results, con't...
HAVING
Like a WHERE clause for groups
List the average product price and lowest product quantity on hand for each product finish that has (a) at least one product with two or more units on hand, and (b) at least 3 products with that finish.
SELECT Product_finish, AVG(Standard_Price), MIN(Qty_on_hand)
FROM Product_t
GROUP BY Product_finish
HAVING MIN (Qty_On_hand) >= 2
AND COUNT (Product_id) >=3;

46. Accessing data in multiple tables

47. Querying Multiple Tables
Nested Queries (aka Subqueries)
Joins
(Inner) Join
Self Join
(Outer) Left Join
Checking Non-Existence Conditions
NOT IN
NOT EXISTS
Creating Views of data

48. subqueries Placing an "inner" query in WHERE clause
Inner queries must SELECT only one column
Column selected by "inner" query must match column in WHERE clause of “outer" query
Show all orders placed by customers who live in states that do NOT end in 'A'. Show orders in descending order.
SELECT Order_ID
FROM Order_t
WHERE Customer_ID IN
(SELECT Customer_ID
FROM Customer_t
WHERE State NOT LIKE '_A')
ORDER BY Order_ID DESC;

49. Subqueries, cont…
Which customers have not placed orders? Show customer IDs and names, sorted by name.
SELECT customer_id, customer_name
FROM customer_t
WHERE customer_id NOT IN
(SELECT _____________
FROM order_t)
ORDER BY customer_name;

50. Subqueries, cont…
Revisit: Which 2 products have the highest inventory?
SELECT TOP 2 WITH TIES product_id, product_description,
qty_on_hand
FROM product_t
ORDER BY qty_on_hand DESC;
SELECT product_id, product_description,
FROM Product_t
WHERE qty_on_hand IN
(SELECT DISTINCT TOP 2 qty_on_hand
FROM product_t
ORDER BY qty_on_hand DESC);

51. joins Bring data together from multiple rows/tables Several Types
Use common column in both rows/tables
Common columns can have same or different names
Must use table_name.column_name to distinguish columns with same names
Can specify one or multiple tables to connect
Use WHERE or FROM clause to connect tables
Several Types
Cross Join
(Inner) Join
Self Join
(Outer) Left Join
(Outer) Right Join
(Outer) Full Join
See

52. (Inner) join
Retrieve Customer Names, Customer IDs, and Order Dates of orders placed after Nov 1, 2000.
SELECT Customer_t.Customer_ID,
Customer_Name, Order_date
FROM Customer_t, Order_t
WHERE Order_date > '01-NOV-00'
AND Customer_t.Customer_ID = Order_t.Customer_ID;

53. (Inner) joins, con't…
List descriptions of all products ordered by customer 1.
SELECT Product_description
FROM Order_Line_t, Order_t, Product_t
WHERE Order_t.Customer_ID = 1
AND Order_t.Order_ID = Order_Line_t.Order_ID
AND Order_Line_t.Product_ID = Product_t.Product_ID;

54. (inner) joins, con't…
List descriptions of all products ordered by customer 1.
SELECT Product_description
FROM (Order_Line_t ol INNER JOIN Order_t o
ON ol.Order_ID = o.Order_ID)
INNER JOIN Product_t p
ON ol.Product_ID = p.Product_ID
WHERE o.Customer_ID = 1;

55. (Inner) joins, con't… Let's combine concepts!
Assuming all orders need to be filled, which products do not have enough quantity on hand to fill their orders?
Show the product ID, description, the quantity of the product on hand, and the total quantity of the product ordered.

56. Self joins Join a table to itself Rows from the same table are related
i.e., recursive relationships
Primary and Foreign keys in same table, different rows

57. Self joins, con't…
For each customer who has an owner, show the customer's name and their owner's name.
CUSTOMER_T

58. Self joins, con't…
(fk)

59. Self joins, con't…
For each customer who has an owner, show the customer's name and their owner's name. c. id
c.name
c.addr
c.city
c.state
c.postal_cd
c.ownid
o.id
o.name
o.addr
o.city
o.state
o.postal_cd
o.ownid 1
contemporary casuals
1355 s. hines blvd
gainesville fl
32601 10
seminole interiors
2400 rocky point dr.
seminole
34646 2
value furniture
15145 x.w.17th st.
plano tx
75094 6
furniture gallary
325 flatiron dr.
boulder co
80514 5
impressions
5585 westcott ct.
sacremento ca
94206 14
kaneohe homes
112 kiowai st.
kaneohe hi
96744 8
california classics
816 peach rd.
santa clara
96915 15
mountain scenes

60. Self joins, con't…
For each customer who has an owner, show the customer's name and their owner's name.
SELECT C.Customer_name AS "Customer", O.Customer_name AS "Owner"
FROM Customer_t C, Customer_t O
WHERE C.Owner_ID = O.Customer_ID;

61. Outer joins Left (Outer) Joins
Brings data together from multiple rows/tables
Use common column in both rows/tables
Retrieves all rows from first table, and only matching rows from second table
Use table_name.column_name to distinguish columns
Can specify TWO tables at a time to connect
Use FROM clause to connect tables
List products that have not been ordered
(NOTE: include product IDs and descriptions)
SELECT p.Product_ID, p.Product_Description
FROM Product_t p LEFT JOIN Order_line_t ol
ON p.Product_ID = ol.Product_ID
WHERE ol.Product_ID IS NULL;

62. Querying Multiple Tables, con't...
Checking Non-Existence
List customers who have NOT ordered computer desks
(NOTE: include customers who have not placed ANY orders)
SELECT Customer_ID, customer_name
FROM Customer_t
WHERE Customer_ID NOT IN
(SELECT Customer_ID
FROM Order_t, Order_line_t, Product_t
WHERE Order_t.Order_ID = Order_line_t.Order_ID
AND Order_line_t.Product_ID = Product_t.Product_ID
AND Product_Description LIKE '%computer desk%');

63. Querying Multiple Tables, con't...
Checking Non-Existence, con't...
List customers who have NOT ordered computer desks
(NOTE: include customers who have not placed ANY orders)
SELECT Customer_ID, customer_name
FROM Customer_t c1
WHERE NOT EXISTS
(SELECT *
FROM Order_t o, Order_line_t ol, Product_t p
WHERE o.Order_ID = ol.Order_ID
AND ol.Product_ID = p.Product_ID
AND Product_Description LIKE '%computer desk%'
AND c1.customer_id = o.customer_id);

64. Querying Multiple Tables, con't…
Derived Tables
Placing an "inner" query in the FROM clause
Must use table alias for derived table
SELECT col(s)
FROM (SELECT col(s) FROM table(s) WHERE…) tblalias
[WHERE …];
Retrieve Customer Names, Customer IDs, and Order Dates of orders placed after Nov 1, 2000.
SELECT xyz.customer_id, xyz.customer_name, xyz.order_date
FROM (SELECT c.Customer_ID, c.Customer_Name, Order_Date
FROM Customer_t c, Order_t o
WHERE Order_date > '01-NOV-00'
AND c.Customer_id = o.Customer_id) XYZ;
Table Alias REQUIRED!

65. Querying Multiple Tables, con't…
Derived Tables, cont…
What product finish has the highest average price?
SELECT Product_finish, AVG(Standard_Price)
FROM Product_t
GROUP BY Product_finish
HAVING AVG(Standard_Price) =
(SELECT MAX(AVG(Standard_Price))
GROUP BY Product_finish);

66. Querying Multiple Tables, con't…
Derived Tables, cont…
What product finish has the highest average price?
SELECT Product_finish, AVG(Standard_Price)
FROM Product_t
GROUP BY Product_finish
HAVING AVG(Standard_Price) =
(SELECT MAX(Price)
FROM (SELECT AVG(Standard_Price) AS Price FROM Product_t
GROUP BY Product_finish)
TempTbl );
Table Alias REQUIRED!

67. VIEWs Dynamic vs. "Materialized" Why use views?
Simplify queries
Rename columns
Security
CREATE VIEW view_name AS
SELECT …… ;

68. VIEWs, cont…
Retrieve all the data elements required to create a customer invoice
SELECT c.customer_id, customer_address, o.order_id, p.product_id, product_description, standard_price, ordered_quantity, standard_price*ordered_quantity AS "line item cost"
FROM customer_t c, order_t o, order_line_t ol, product_t p
WHERE c.customer_id = o.customer_id
AND o.order_id = ol.order_id
AND ol.product_id = p.product_id;
Create a view that retrieves all the data elements required to create a customer invoice
CREATE VIEW invoice_view AS
SELECT o.customer_id, customer_address, ol.order_id, ol.product_id, product_description, standard_price, ordered_quantity as quantity, standard_price*ordered_quantity AS "line item cost"

69. CASE Analogous to IF-THEN-ELSE within SQL Examples: See:
SELECT product_id, CASE
WHEN product_id = 3 THEN order_id
WHEN product_id = 8 THEN product_id
ELSE ordered_quantity
END
AS "order#, product#, or QN"
FROM order_line_t;
SELECT CASE WHEN state = 'FL' THEN postal_code END
FROM customer_t
WHERE customer_id <> 9;
See:
(syntax for different dbms's)

70. Summary SQL Server Architecture Types of SQL Server Products
Components
Where user data and metadata are stored
How applications fit in
Types of SQL Server Products
Our focus is on the query services and the RDBMS
How to access SQL Server for class
History of SQL
SQL Environment
SQL Language
DDL
DML
Basic Query
Search Conditions
Categorizing and Sorting Results
Querying Multiple Tables
Various flavors of Joins
Various Flavors of Subqueries
Additional SQL commands

71. Next Time… 3/20 *** Quiz 2 *** 4/3 Database Stored Code
Chapter 7: Advanced SQL
Pages 320 – 327
4/3 *** Assignment 4 Due ***