The writer is asking how to count the number of replies in a topic, when replies are only associated with threads, which are in turn associated with topics.
This question asks for the 5th highest salary from the "Employees" table. The example input is a table with id, name, and salary columns, and the example output is a table with a salary column.
This technical problem involves writing an SQL query that returns the top 3 most purchased products by customers. The example input and output are provided.
To find the top 10 customers by total purchase amount, write a SQL query that orders the customers by purchase_amount in descending order.