databases and sql for data science with python coursera course answers
Final Exam
1. True or False: The SELECT statement is called a query, and the output we get from executing the query is called a result set.
- False
True
2. Which of the following SQL statements will delete the authors with IDs of A10 and A11?
- DELETE (‘A10’, ‘A11’) FROM AUTHOR
- DELETE FROM AUTHOR WHERE AUTHOR_ID IN (‘A10’, ‘A11’)
- DELETE FROM AUTHOR WHERE AUTHOR_ID IS (‘A10’, ‘A11’)
- D: DELETE AUTHOR_ID IS (‘A10’, ‘A11’) FROM AUTHOR
3. The primary key of a relational table uniquely identifies each _______ in a table.
- attribute
- relation
- column
- row
4. The basic categories of the SQL language based on functionality are Data Definition Language (DDL) and _________.
- Data Input Language (DIL)
- Data Manipulation Language (DML)
- Data Entry Language (DEL)
- Data Update Language (DUL)
5. When querying a table called Representative that contains a list of representatives and the state that they represent, which of the following queries will return the number of representatives from each state?
- SELECT State, count(State) FROM Representative
- SELECT State, count(State) FROM Representative GROUP BY State
- SELECT distinct(State) FROM Representative
- SELECT State, distinct(State) FROM Representative GROUP BY State
6. You want to retrieve a list of books that have between 450 and 600 pages. Which clause would you add to the following SQL statement: SELECT Title, Pages FROM Book ________________________________
- IF Pages >= 450 and Pages <= 600
- WHERE Pages = 450
- WHERE Pages >= 450 and pages <= 600
- WHERE Pages 450 – 600
7. Which of the following queries will retrieve the LOWEST value of PRICE in a table called PRODUCTS?
- SELECT LOWEST(PRICE) FROM PRODUCTS
- SELECT LEAST(PRICE) FROM PRODUCTS
- SELECT MIN(PRICE) FROM PRODUCTS
- SELECT MAX(PRICE) FROM PRODUCTS
8. Which of the following queries will retrieve the last name of the employee who earns the lowest salary?
SELECT LAST_NAME FROM EMPLOYEES WHERE SALARY =
(SELECT MIN(SALARY) FROM EMPLOYEES)
- SELECT LAST_NAME, MIN(SALARY) FROM EMPLOYEES GROUP BY F_NAME
- SELECT MIN(SALARY) FROM EMPLOYEES
- SELECT FIRST_NAME FROM EMPLOYEES WHERE SALARY IS LOWEST
9. A database cursor is a control structure that;
- Does not allow communication with a database
- Enables traversal over the records in a database
- Does not allow you to create tables
- Does not allow you to update records within a database
10. To query data from tables in database a connection to the database needs to be established. Which of the following is required to establish a connection with a relational database from a Python notebook?
- Database Name
- All of the above
- A SQL or Database API
- Username and Password
