Which practice helps avoid N+1 queries?

• A. Proper joins and batching.
• B. Avoiding joins altogether.
• C. Doing separate queries for every row.
• D. Using select *.

Answer: (A)

Avoiding N+1 queries is all about reducing how many times your code hits the database to fetch related data. The problem happens when you load a list of items (N items) and then, for each item, run another query to get its related data, resulting in N extra queries on top of the initial one.

Using proper joins and batching addresses this by pulling related data in as few queries as possible. A join combines related tables in a single query so you get both the main records and their associations in one go. Batching groups multiple lookups into one request, such as fetching all needed related rows with a single IN clause, or using an ORM's eager-loading mechanisms to load associations alongside the primary data. The net effect is far fewer database round-trips—often just one query or a small, predictable number of queries.

The other options don’t fix the underlying issue. Avoiding joins can lead to more queries instead of fewer, doing separate queries for every row is the exact N+1 pattern, and selecting all columns doesn’t impact the number of queries or how data is retrieved.