Practice Aggregate Functions (1.4.2) - Database Management

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6 sample questions

Question 1.
What function would you use to count the number of active users?
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It's the function that counts rows.
Question 2.
What does SUM() do in SQL?
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Think of it as finding the total sales.
3Question 3.
What does COUNT() do in SQL?
- Counts the number of distinct values
- Counts the total number of rows
- Calculates the average
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Consider what it means to count rows.
4Question 4.
True or False: SUM() can only be used on text columns.
- True
- False
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Remember what kind of data you can sum up.
Question 5.
Write a SQL query that uses both SUM() and AVG() to display the total sales and the average order value from a sales table.
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Use both functions in the SELECT statement.
Question 6.
Explain how you would use COUNT() with a GROUP BY clause to determine how many employees work in each department.
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Consider how you group data and then count it.

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