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Test your understanding with targeted questions related to the topic.
Question 1
Easy
What does a LEFT JOIN do in SQL?
π‘ Hint: Think about the tables involved and which records are included.
Question 2
Easy
In which scenario would you prefer using LEFT JOIN over INNER JOIN?
π‘ Hint: Consider what happens when there's missing data.
Practice 4 more questions and get performance evaluation
Engage in quick quizzes to reinforce what you've learned and check your comprehension.
Question 1
What does LEFT JOIN return when there are no matching records in the right table?
π‘ Hint: Consider what LEFT stands for in LEFT JOIN.
Question 2
True or False: LEFT JOIN omits records from the left table if there are no matches in the right table.
π‘ Hint: Reflect on the definition and purpose of LEFT JOIN.
Solve 1 more question and get performance evaluation
Push your limits with challenges.
Question 1
Suppose you have two tables: 'employees' and 'departments'. Write a LEFT JOIN query to list all employees and their departments, ensuring to include employees who might not belong to any department.
π‘ Hint: Consider how employees relate to departments.
Question 2
Imagine you are analyzing a customer database where some customers have not made any purchases. Formulate a LEFT JOIN query that tallies the purchases made by each customer and returns all customers regardless of whether they made a purchase or not.
π‘ Hint: Remember to group your results to get counts.
Challenge and get performance evaluation