SQL interview questions

How to prepare for a SQL interview

Most SQL interviews reuse a small set of patterns: aggregate per group, join and keep or drop unmatched rows, rank within groups, compare a row to the one before it, and turn a messy question into steps. Practice each pattern until you can write it without looking it up.

Start with the easy questions in each topic, then time yourself on medium and hard ones. Say your approach out loud before you write the query; interviewers care about how you get there as much as the final answer.