Join with Aggregation — Solution & ExplanationProblems / Join with Aggregation / EditorialApproach

JOIN employees to departments on dept_id to enrich each employee row with the department name.

GROUP BY dept_name and compute the three aggregates.

Order by total_salary descending.

Key InsightThe join happens before the aggregation. First you combine the data, then you summarize it. This is a very common pattern in analytics queries.Hints

First JOIN to get department names alongside employees, then GROUP BY the department.

COUNT(*) counts all employees per group; SUM and AVG operate on the salary column.

Round AVG to 2 decimal places.

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