What is the N+1 query problem and how to solve it?

The N+1 query problem occurs when an application first queries a list of records from a database table, then subsequently queries each record individually. This approach is flawed because it results in multiple trips to the database server, leading to increased time and resource usage. To fix this issue, developers should refactor their code to use a single query that incorporates all necessary data, such as joins or aggregations, which can significantly improve performance.