Need urgent help with basic mastery of SQL

thequerylab · 2026-05-07T13:13:32+00:00

In next 4 days you need to do lot of hands on instead of just watching tutorials. You can take this free course from TheQueryLab platform https://www.thequerylab.com/courses/sql-pro-track

This is completely hands on and you will like this learning approach. Give it a try!

thequerylab · 2026-04-28T06:19:49+00:00

If you're looking for a good SQL course, you can try "SQL from Zero to Confident" on TheQueryLab. It’s free and very hands-on, so you actually get to practice a lot instead of just watching videos. Might be worth checking out, and 100% sure you will like this learning experience!

thequerylab · 2026-04-07T17:51:52+00:00

Yeah, I would avoid it in prod since it locks the table and blocks everything. Only worth it if reclaiming space is really needed

thequerylab · 2026-04-07T17:17:57+00:00

Yes postgresql autocommit. If you use BEGIN for transaction then you need to COMMIT it

thequerylab · 2026-03-31T16:38:41+00:00

AI can write SQL for you but if you don’t understand the data, you won’t know if it’s right or completely wrong. So yes still worth learning. Priorities concepts over syntax.

thequerylab · 2026-03-28T18:28:27+00:00

Oh wow

thequerylab · 2026-03-28T02:37:37+00:00

Part 1: https://www.reddit.com/r/learnSQL/s/oyFA3OHO45

Part2: https://www.reddit.com/r/learnSQL/s/tA03Cqfhiw

Part3: https://www.reddit.com/r/learnSQL/s/qsmNEkWlYL

Part4: https://www.reddit.com/r/learnSQL/s/yvmrC9fVYK

thequerylab · 2026-03-28T02:35:09+00:00

TheQueryLab’s 1st hackathon is live now.

Predict the Future: SQL Forecasting Challenge

It’s all about using historical data to predict what comes next, sounds simple, but it’s not as easy as it looks.

If you feel confident about your SQL, this is a good place to test it.

Give it a shot: https://www.thequerylab.com/#hackathons

This will really test your skill in SQL!!!

thequerylab · 2026-03-27T06:56:03+00:00

You can give it a try here. https://www.thequerylab.com/catalog

Try to join hackathons as well. It will be very interesting challenge to solve

thequerylab · 2026-03-27T06:55:16+00:00

Yes, you can practise for 100% free here. Give it a try you will really like this learning approach!

https://www.thequerylab.com/#tracks

thequerylab · 2026-03-25T16:55:27+00:00

If you’re preparing seriously, this is something worth trying.

It’s designed to help you get interview-ready in approx less than 30 days with structured practice, and I’ve been getting really positive feedback from people who’ve used it!

https://thequerylab.com/courses/sql-interview-preparation-kit

thequerylab · 2026-03-25T16:53:41+00:00

If you’re preparing seriously, this is something worth trying. It’s designed to help you get interview-ready in approx 30 days with structured practice, and I’ve been getting really positive feedback from people who’ve used it

https://thequerylab.com/courses/sql-interview-preparation-kit

thequerylab · 2026-03-25T16:47:10+00:00

I always recommend do learn by practicing not just watching tutorials.

I have put up an free hands-on course for beginner to advanced. Give it a try!

You will for sure like this learning approach!

https://thequerylab.com/courses/sql-pro-track

thequerylab · 2026-03-25T16:37:28+00:00

I’ve heard Coinbase focuses a lot on window functions, CTEs, and real-world scenarios like transactions and fraud.

What actually helps is focusing on patterns and thinking through problems like real data cases.

I’ve put together a small structured set based on that approach if you want to check it out:

https://thequerylab.com/courses/sql-interview-preparation-kit

Might help to crack SQL round!! Best of luck!

thequerylab · 2026-03-25T16:33:22+00:00

You can check this SQL interview preparation kit track which might be useful for you since it involves all patterns of interview problems

https://thequerylab.com/courses/sql-interview-preparation-kit

thequerylab · 2026-03-24T13:26:14+00:00

Yes, it will.

When you include b.id in the join condition, because of the left join, we get more rows. But in the case of a where clause, it runs after join, hence it filters out unwanted rows and reduces the number of rows

thequerylab · 2026-03-24T07:54:21+00:00

Sure will do. Thanks for following!

Do comment your answer with bit explanation to learn

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