Practice Left Join (2.2) - SQL for Business Analysts - Business Analysis

Practice: LEFT JOIN

Lesson 2.2SQL for Business Analysts

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9 questions

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2 cards from this section. Quick, good the night before a test.
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3 questions · about 2 min · pass mark 70%. Hints available.
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6 sample questions

Question 1.
What does a LEFT JOIN do in SQL?
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Think about the tables involved and which records are included.
Question 2.
In which scenario would you prefer using LEFT JOIN over INNER JOIN?
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Consider what happens when there's missing data.
3Question 3.
What does LEFT JOIN return when there are no matching records in the right table?
- Only matching records
- All records from the left table
- No records
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Consider what LEFT stands for in LEFT JOIN.
4Question 4.
True or False: LEFT JOIN omits records from the left table if there are no matches in the right table.
- True
- False
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Reflect on the definition and purpose of LEFT JOIN.
Question 5.
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.
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Consider how employees relate to departments.
Question 6.
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.
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Remember to group your results to get counts.

5 more questions in this section. Enroll free to practise them all.