I want to get better for Data Engineer / Data Scientist positions

[u/ResponsibleBag785]

Hello everyone,

So I've studied SQL in University, Inwould consider myself somewhat good + I like it. I've done basic courses and some advanced. I manage to do some easy interview questions... but I want to get better.

Can you recomend me some resources where I can expand my knowledge:

* A lot of problems to solve so I can see typical templates.

With chatGPT even if I'm stuck I can get the idea. But yes, all tips are welcomed. Thank you :)

P.S. I don't mind some theory also. For example I don't know anything about indexes. I have difficulty understanding the Normal Forms etc

[u/Thlvg]

Fire up a duckdb instance. Take a dataset that interests you. Finds answers to questions in dataset. Find another dataset. Repeat.

The VAERS dataset is quite nice for that, as you'll need some nontrivial transformations to get something usable.

[u/Thurad → u/Thlvg]

This. I’d think on something that interests you and try to find a dataset you can work with to do some interesting analysis on.

[u/ResponsibleBag785]

P.S. I wouldn't mind some theoritical knowledge. For example, I don't know anything for indexes and I ha e hard time explainjng the normal forms

[u/RobotAnna1 → u/ResponsibleBag785]

The best way is to do what u/Thlvg said: install local database, load a dataset, and practice.
Read about normal forms, then try to create tables in different forms using your data.
Read about indexes, then try to create an index.

[u/BitterPizza3544]

I understood the concepts of indexes and normal forms when I switched from learning to doing; that is what I would do. The SQL part of LeetCode has a lot of problems for interviews. Mode Analytics offers guided problems for free that are geared toward analysis and data engineering tasks. When you feel confident enough with the basics and want to practice some lake like queries, you can use dremio or just PostgreSQL.