Question Archive

What does the following query do? SELECT dept_id, AVG(salary) FROM employees GROUP BY dept_id HAVING AVG(salary) > 60000

SQL FundamentalsMedium

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What does the CONCAT function do in SQL?

SQL FundamentalsMedium

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Which aggregate function should you use to find the total revenue per product category?

SQL FundamentalsMedium

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What does the SQL INTERSECT operator return?

SQL FundamentalsMedium

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What is the difference between CHAR and VARCHAR data types?

SQL FundamentalsMedium

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What does the UNIQUE constraint guarantee?

SQL FundamentalsMedium

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What happens when you DELETE rows without a WHERE clause?

SQL FundamentalsMedium

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What does the NOT NULL constraint enforce on a column?

SQL FundamentalsMedium

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What is the purpose of the OFFSET clause when used with LIMIT?

SQL FundamentalsMedium

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Which of the following correctly describes a CROSS JOIN?

SQL FundamentalsMedium

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What does the CASE expression return when no WHEN condition matches and no ELSE is provided?

SQL FundamentalsMedium

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What is a self-join?

SQL FundamentalsMedium

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What does the DISTINCT keyword do when used with COUNT?

SQL FundamentalsMedium

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Which SQL statement is used to modify existing records in a table?

SQL FundamentalsMedium

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What is the result of a FULL OUTER JOIN?

SQL FundamentalsMedium

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What does the COALESCE function return?

SQL FundamentalsMedium

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What is the difference between WHERE and HAVING in SQL?

SQL FundamentalsMedium

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What does index cardinality measure and why does it matter for query optimization?

SQL Data AnalystMedium

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