This chapter is from the book
This chapter is from the book
This chapter is from the book
Workshop
The following workshop is composed of a series of quiz questions and practical exercises. The quiz questions are designed to test your overall understanding of the current material. The practical exercises are intended to afford you the opportunity to apply the concepts discussed during the current hour, as well as build upon the knowledge acquired in previous hours of study. Please take time to complete the quiz questions and exercises before continuing. Refer to Appendix C, "Answers to Quizzes and Exercises," for answers.
Quiz
What type of join would you use to return records from one table, regardless of the existence of associated records in the related table?
The join conditions are located in what part of the SQL statement?
What type of join do you use to evaluate equality among rows of related tables?
What happens if you select from two different tables but fail to join the tables?
Use the following tables:
Is the following syntax correct for using an OUTER JOIN?
|
ORDERS_TBL |
|||
|
ORD_NUM |
VARCHAR(10) |
NOT NULL |
primary key |
|
CUST_ID |
VARCHAR(10) |
NOT NULL |
|
|
PROD_ID |
VARCHAR(10) |
NOT NULL |
|
|
QTY |
Integer(6) NOT NULL |
|
|
| ORD_DATE | DATETIME |
|
|
|
PRODUCTS_TBL |
|||
|
PROD_ID |
VARCHAR(10) |
NOT NULL |
primary key |
|
PROD_DESC |
VARCHAR(40) |
NOT NULL |
|
| COST | DECIMAL(,2) NOT NULL |
|
|
SELECT C.CUST_ID, C.CUST_NAME, O.ORD_NUM FROM CUSTOMER_TBL C, ORDERS_TBL O WHERE C.CUST_ID(+) = O.CUST_ID(+)
Exercises
Invoke MySQL, point to your learnsql database, and type the following code and study the result set (Cartesian product):
Type the following code to properly join the EMPLOYEE_TBL and EMPLOYEE_PAY_TBL tables:
Write a SQL statement to return the EMP_ID, LAST_NAME, and FIRST_NAME from the EMPLOYEE_TBL and SALARY and BONUS from the EMPLOYEE_PAY_TBL.
What is the average employee salary per city?
Try writing a few queries with join operations on your own.
SELECT E.LAST_NAME, E.FIRST_NAME, EP.DATE_HIRE FROM EMPLOYEE_TBL E, EMPLOYEE_PAY_TBL EP;
SELECT E.LAST_NAME, E.FIRST_NAME, EP.DATE_HIRE FROM EMPLOYEE_TBL E, EMPLOYEE_PAY_TBL EP WHERE E.EMP_ID = EP.EMP_ID;