SQL Joins and Group By Quiz

What is an inner join in SQL?

• An inner join in SQL combines rows from two or more tables based on a random column

• An inner join in SQL combines rows from two or more tables based on a related column between them.

• An inner join in SQL combines rows from two or more tables based on the sum of their values

• An inner join in SQL combines rows from two or more tables based on the maximum value in a column

How is an inner join different from an outer join?

• An inner join returns all the rows from one table and only the matching rows from the other table

• An inner join returns only the rows that have matching values in one table

• An inner join returns only the rows that have matching values in both tables being joined, while an outer join returns all the rows from one table and only the matching rows from the other table.

• An inner join returns all the rows from both tables being joined

Complete the query:

SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderAmount, Orders.OrderDate
FROM Orders
INNER JOIN _______ ON _____________ = _____________;

• INNER JOIN Orders ON Orders.OrderID=Orders.CustomerID;

• INNER JOIN Customers ON Customer.CustomerID=Customers.CustomerID;

• INNER JOIN Orders ON Orders.CustomerID=Customers.CustomerID;

• INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;

Refer to the exhibit. Which type of SQL JOIN operation would return all the rows from Table 1 and Table 2?

• LEFT JOIN

• RIGHT JOIN

• INNER JOIN

• CROSS JOIN

When would you use an inner join in a SQL query?

• To retrieve all the rows from the left table and the matched rows from the right table.

• To retrieve only the rows that have non-matching values in both tables being joined.

• To retrieve only the rows that have matching values in both tables being joined.

• To retrieve all the rows from the right table and the matched rows from the left table.

Which JOIN clause would join the two tables Orders and Customers, using the CustomerID field in both tables as the relationship between the two tables?
SELECT *
FROM Orders
LEFT JOIN Customers ON ____________ = ______________;

• ON Customer.CustomerID=Orders.CustomerID

• ON Orders.CustomerID=Customers.CustomerID

• ON Orders.CustomerID=Orders.CustomerID

• ON Customers.CustomerID=Customers.CustomerID

Refer to the exhibit. A data analyst writes a SQL query to extract information from multiple tables in the Movies database. To complete the ON command, what needs to be entered in place of the question mark in this query?
SELECT m.Title, m.Date, r.AuthorName, r.Score, r.Comment, r.Date
FROM Review AS r
JOIN Movie AS m
ON m.Title = ?;

• r.MovieTitle;

• r.ID;

• r.Comment;

• r.Score;

What is the purpose of the GROUP BY clause in SQL?

• To sort the rows in ascending order

• To group rows with the same values in specified columns

• To delete duplicate rows from the table

• To update the values in specified columns

What is the difference between the WHERE clause and the GROUP BY clause in SQL?

• The WHERE clause groups the result set by one or more columns, while the GROUP BY clause filters rows based on a condition.

• The WHERE clause filters rows based on a condition, while the GROUP BY clause groups the result set by one or more columns.

• The WHERE clause is used for joining tables, while the GROUP BY clause is used for selecting specific columns.

• The WHERE clause is used for mathematical operations, while the GROUP BY clause is used for string manipulations.

When would you use the GROUP BY clause in a SQL query?

• To join multiple tables in the query

• To order the result set in ascending order

• To group the result set by one or more columns.

• To filter the result set based on a condition