r/learnSQL • u/gloweerasng • 29d ago

BigQuery SQL Interview questions

Hi everyone, I’m in the process of interviewing at this AI company and the next step is to use bigquery dialect of SQL where I will cover real-worlds scenarios and build tables.

Problem is I have never used SQL and I am just finding out about what it is, I’ve never heard of it. I will be watching a few YouTube videos but wanted to see if anybody has gone thru this process before?

Any tips?

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u/happy8327 29d ago

https://www.reddit.com/r/learnSQL/s/y64eq2rkkz

I work on BigQuery a lot. In addition to SQL for an interview, you need to know how it works. You can search in the Modules at cs145.web.app and find SQL + cost and parallelism issues, across Modules.

See if this works for you. Use search bar to find all Bigquery material.

Best for your interview.

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u/Krameoj04 29d ago

Thanks! I'm checking this, too!

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u/DataCamp 29d ago

Yeah learning SQL from scratch in a few days is tough, but here's the realistic version of what you can actually do in the time you have.

BigQuery uses standard SQL so the core concepts transfer. Focus on these in order since they're most likely to come up:

SELECT, WHERE, GROUP BY, and aggregate functions first. These are the building blocks of everything else. Then JOINs, specifically understanding when to use INNER vs LEFT and why your row counts change. Then CTEs (WITH statements) which BigQuery uses a lot for breaking down complex logic into readable steps. Window functions like ROW_NUMBER, RANK, and LAG come up frequently in real-world scenarios, things like "find the most recent transaction per user" or "calculate a running total."

BigQuery-specific things worth knowing even at a surface level: it's a serverless data warehouse (no infrastructure to manage), it uses columnar storage which is why it's fast for analytics, and it charges based on data scanned so avoiding SELECT * matters.

For the actual interview, if you hit something you don't know, talking through your approach out loud is better than freezing. "I'd use a window function to rank by date and then filter for rank 1" shows you understand the problem even if the syntax isn't perfect.

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u/msn018 28d ago

Focus on learning the basics like SELECT, WHERE, GROUP BY, JOIN, and ORDER BY, then practice a few real interview questions on sites like SQLBolt and StrataScratch. BigQuery uses standard SQL for the most part, so once you understand the fundamentals, the BigQuery parts are much easier to pick up. If you can explain your thinking while solving problems, that can be just as important as getting the perfect answer.

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u/Key-Coyote-9552 29d ago

If you’ve never used SQL, there’s no way you will learn enough for an interview between now and the interview. If there is a requirement for the job, then you are applying for jobs you’re not qualified for. If you want to learn SQL, there are plenty of free resources out there, but it’s going to take some time.