One of the biggest challenges in working with SQL is performance. A query that works fine on a test dataset can slow to a crawl when applied to millions of rows in production.

From creating the right indexes, restructuring joins, and breaking down complex queries into smaller steps, to analyzing execution plans there are so many strategies that data professionals rely on. Some swear by indexing, others by query refactoring, and some by caching results.

The real art lies in knowing which approach to apply in which situation.

What optimization practices have you found most effective in your real-world projects?

Deep learning is being applied everywhere from computer vision and natural language processing to healthcare, finance, and autonomous systems.

But not every problem benefits equally from these models, and implementing them in practice often comes with challenges like data quality, computational resources, and interpretability.

While some industries have already seen transformative results, others are still exploring how to use these tools effectively.

It would be interesting to hear from you : what examples have surprised you with their success, and where have you seen deep learning fall short of expectations?

Let’s be honest most of us rely on SELECT, JOIN, and WHERE day in and day out. But every once in a while, there’s that one SQL function or technique that just clicks and saves hours of pain.
Maybe it was a window function, maybe it was a sneaky little CTE or COALESCE that fixed a broken report. What’s that one underrated SQL trick that changed the game for you?

The demand for data skills is growing fast, and freelancing can open up some great opportunities. Many companies want experts who can jump in and help with projects without long-term commitments.

That said, freelancing isn’t always easy. Finding clients, setting your rates, and managing work on your own takes effort and patience.

If you’re freelancing or thinking about it, this is a space to share your real experiences and learn from others.

Is there a way to append the excel tabs together is they are in the same format? I do not have any tools. If I have to use any free tool, which one should it be?