databases and sql for data science with python coursera week 1 quiz answers

Practice Quiz

1. Which of the following statements are correct about databases?

  • A database is a repository of data
  • There are different types of databases – Relational, Hierarchical, No SQL, etc.
  • A database can be populated with data and be queried
  • All of the above

2. True or False: A SELECT statement is used to retrieve data from a table.

  • True
  • False

3. You are working on a Film database, with a FilmLocations table. You want to retrieve a list of films that were released in 2019.You run the following query but find that all the films in the FilmLocations table are listed.

SELECT Title,ReleaseYear, Locations FROMFilmLocations;

What is missing?

  • A WHERE clause to limit the results to films released in 2019.
  • A LIMIT clause to limit the results to films released in 2019.
  • Nothing, the query is correct.
  • A DINSTINCT clause to specify a distinct year.

4. Which of the following statements would you use to add a new instructor to the Instructor table.

  • ADD INTO Instructor(ins_id, lastname, firstname, city, country)

    VALUES(4, ‘Doe’, ‘John’, ‘Sydney’, ‘AU’);

  • UPDATE Instructor(ins_id, lastname, firstname, city, country)

    WITH VALUES(4, ‘Doe’, ‘John’, ‘Sydney’, ‘AU’);

  • INSERT INTO Instructor(ins_id, lastname, firstname, city, country)

    VALUES(4, ‘Doe’, ‘John’, ‘Sydney’, ‘AU’);

  • SELECT Instructor(ins_id, lastname, firstname, city, country)

    FROM VALUES(4, ‘Doe’, ‘John’, ‘Sydney’, ‘AU’);

5. What is the function of a WHERE clause in an UPDATE statement?

  • A WHERE clause enables you to list the column and data to be updated.
  • A WHERE clause enables you to specify which rows will be updated.
  • A WHERE clause enables you to specify a new table to receive the updates.
  • A WHERE clause is never used with an UPDATE statement.

Graded Quiz: Basic SQL

6. True or False: The INSERT statement can be used to insert multiple rows in a single statement.

  • True
  • False

7. Assume there exists an INSTRUCTOR table with several columns including FIRSTNAME, LASTNAME, etc. Which of the following is the most likely result set for the following query:

SELECT DISTINCT(FIRSTNAME) FROM INSTRUCTOR

  • LEON

    LEON

    PAUL

    PAUL

  • LEON

    PAUL

    JOE

  • LEON

    PAUL

    LEON

    JOE

  • LEON KATSNELSON

    PAUL ZIKOPOLOUS

    JOE SANTARCANGELO

8. What does the following SQL statement do?

UPDATE INSTRUCTOR SET LASTNAME = 'Brewster' WHERE LASTNAME = 'Smith'

  • Changes all rows for the instructor with a last name of Smith to have a last name of Brewster.
  • Change the row for the instructor with a last name of Brewster to have a last name of Smith.
  • Change all rows in the table to have a last name of Smith.
  • Change all rows in the table to have a last name of Brewster.

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