Check these solutions from our community:

Given a table of data representing customer orders, this SQL query finds the order with the highest total value.

About this solution: The solution above is optimal because it uses the GROUP BY clause to group the data by customer_id and order_id, and then uses the SUM function to calculate the total value of each order.
The solution then uses the ORDER BY clause to sort the data by total_value in descending order, and then uses the LIMIT clause to return only the first row.

To find the top 5 most expensive items in the database, write a SQL query that orders the items by price in descending order.

About this solution: The solution above is optimal because it uses the ORDER BY and LIMIT clauses to sort the items by price in descending order and then limit the results to the top 5 items.

Given a table of data with two columns, write a SQL query to find the median value in the second column.

About this solution: The candidate's solution is correct and uses the median function, which is a built-in function in SQL.

A system that can support 1,000 concurrent users is needed.

About this solution: The candidate's solution is incomplete. The candidate does not mention how to design the system to support a large number of concurrent users. The candidate only mentions horizontal scaling, which is one approach to scaling. The candidate does not mention other approaches, such as vertical scaling, which could also be used to support a large number of concurrent users.

Write a SQL query that returns the 5 most recent articles from a table of articles, sorted by published date.

About this solution: The candidate's solution is correct and demonstrates a good understanding of SQL. The solution is optimal because it uses the ORDER BY and LIMIT clauses to sort the articles by published date in descending order and then limit the results to the 5 most recent articles.

Given a table of customer data, this SQL query returns the top 10 customers with the highest average order value.

About this solution: The candidate's solution is complete and solves the problem. The approach is clear and concise.

To find the top 5 most expensive items in our inventory, we can write a SQL query that orders the items by price in descending order and then limit the output to the first 5 results.

About this solution: The candidate's solution is correct and demonstrates a good understanding of SQL. The solution is optimal because it uses the ORDER BY and LIMIT clauses to sort the items by price in descending order and then limit the results to the first 5 items.

Write a SQL query to find the customers who have spent more than $1000 in total, given a table of customer orders.

About this solution: The solution above is optimal because it uses the GROUP BY and HAVING clauses to group the orders by customer_id and then filter the results to only include customers who have spent more than $1000.