FULL OUTER JOIN behavior in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all columns from both tables using a FULL OUTER JOIN.

SQL

SELECT * FROM employees [1] departments ON employees.dept_id = departments.id;

Drag options to blanks, or click blank then click option'

AINNER JOIN

BLEFT JOIN

CRIGHT JOIN

DFULL OUTER JOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using INNER JOIN which only returns matched rows.

Using LEFT JOIN or RIGHT JOIN which return unmatched rows from only one table.

The FULL OUTER JOIN returns all rows when there is a match in one of the tables. It includes matched rows and unmatched rows from both tables.

2fill in blank

medium

Complete the code to find all employees and departments, including those without matches.

SQL

SELECT employees.name, departments.name FROM employees [1] departments ON employees.dept_id = departments.id;

Drag options to blanks, or click blank then click option'

AFULL OUTER JOIN

BINNER JOIN

CCROSS JOIN

DSELF JOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using INNER JOIN which excludes unmatched rows.

Using CROSS JOIN which returns all combinations, not just matches.

FULL OUTER JOIN returns all employees and all departments, including those without matching counterparts.

3fill in blank

hard

Fix the error in the join type to correctly perform a FULL OUTER JOIN.

SQL

SELECT * FROM sales [1] customers ON sales.customer_id = customers.id;

Drag options to blanks, or click blank then click option'

AFULL OUTER JOIN

BLEFT JOIN

CRIGHT JOIN

DINNER JOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using LEFT JOIN or RIGHT JOIN which exclude unmatched rows from one side.

Using INNER JOIN which excludes all unmatched rows.

To include all sales and customers, even if they don't match, use FULL OUTER JOIN.

4fill in blank

hard

Fill both blanks to select employee names and department names, including unmatched rows.

SQL

SELECT employees.name AS emp_name, departments.name AS dept_name FROM employees [1] departments ON employees.dept_id [2] departments.id;

Drag options to blanks, or click blank then click option'

AFULL OUTER JOIN

B=

C<>

DLEFT JOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using LEFT JOIN instead of FULL OUTER JOIN.

Using <> instead of = in the ON condition.

The FULL OUTER JOIN includes all rows from both tables. The ON condition uses = to match department IDs.

5fill in blank

hard

Fill all three blanks to select all orders and customers, including unmatched rows, and order by customer name.

SQL

SELECT orders.id, customers.name, orders.amount FROM orders [1] customers ON orders.customer_id [2] customers.id ORDER BY customers.name [3];

Drag options to blanks, or click blank then click option'

AFULL OUTER JOIN

B=

CASC

DDESC

Attempts:

3 left

💡 Hint

Common Mistakes

Using LEFT JOIN or RIGHT JOIN instead of FULL OUTER JOIN.

Using <> in ON condition causing no matches.

Ordering DESC instead of ASC.

Use FULL OUTER JOIN to include all orders and customers. The ON condition uses = to match IDs. Ordering by customer name ascending uses ASC.