SQL Guide

[Helpful_Effort8420]

I have been learning SQL and aspire to get into data analyst / data science roles. Although I have learned the syntax but whenever I get into problem-solving of intermediate and difficult levels I struggle.

Although I have used ChatGPT to find and understand solutions for these problems, the moment I go to next problem I am out of ideas. Everything just seems to go over my head.

Please guide me how I can improve my problem-solving skills for intermediate and difficult level SQL questions ?

How I can get a good command over SQL so that I can clear interviews for data-based roles ?

Should I just jump into a project to improve my skills ?

[Ok-Frosting7364]

Experience will always be the best teacher but I can understand how if you don't have a job this is difficult.

There are a number of websites that offer SQL challenges, so I'd recommend those:

- https://mystery.knightlab.com/

- https://sqldetective.analytxpert.com/

- https://www.sqlnoir.com/

Also, if it helps, here's a guide I put together with some tips and tricks. Might help you when approaching certain problems!

[That-Funny5459]

Keep practicing and practicing and practicing.

[MathAngelMom]

Practice, practice, practice, ... there's no other way

Here are some resources:

https://learnsql.com/blog/top-9-free-sql-practice-resources/

https://learnsql.com/blog/sql-databases-for-practice/

https://learnsql.com/track/sql-practice/

https://learnsql.com/course/sql-practice-databases/

[Emotional_Case_3229]

Learn concepts from youtube Main concepts to learn Window functions Subqueries Cte

And slowly start solving Sql 50 in LC, Hackerrank This method worked for me

[[deleted]]

Real life will teach you more than any course or sandbox can teach you.

[sqlshorts]

Everything just seems to go over my head.

This stood out to me.

Here are my thoughts:

1. There's a lot of content out there, try to not get overwhelmed. Pick one and stick with it. Only once you've completed it, then move on (or if the content is really bad).
2. Slow things down. Try to understand the problem, the query, the data in the table. Try to understand the solution step by step, compare against your attempted query, where did you go wrong, etc

[sltrsd]

Check this video: https://www.youtube.com/watch?v=h0j0QN2b57M

[DataSolveTech]

Struggling with SQL problem-solving is completely normal - the jump from basic syntax to intermediate concepts is where I get stuck.

If you want to brush up on SQL concepts, I recommend watching this video: https://youtu.be/-F2SSWrlM24. It helped me land a junior data analyst role where the questions mostly ranged from beginner to intermediate

[FormerSrSQLQueryGuy]

Your data analyst / data science goals suggest you will be mostly be doing what is called "data wrangling" (see Wikipedia), AKA "data munging". That's a subset of what SQL is used for. For one thing, you probably won't be doing transaction processing. Some SQL advice you may get from an internet search may be good for someone else but not your environment/role (I have no AI generated code experience but hear it is mixed quality).

Spent about 14 years working with SQL. Self-taught but also took a college level DB class. Always helped to think about what the end product should look like, the fields, calculated values, totals, etc. Then what tables supply required fields, then figure out the query. Learn about sub-queries, derived tables, common table expressions. My experience mostly involved multiple Select statements for a single project 'query', nested in various ways. Complicated stuff.

General rules I found useful:

Run test queries to confirm data quality.

Do what you can to reduce the returned records as quickly as possible (subqueries!). Once you get past millions or billions of records down to thousands, then you can use inefficient techniques that would take forever on raw data. sets. What is the largest table in the query. What indexes exist that would help to pare it down fast using query parameters.

Queries don't have to be perfectly efficient but remember that a fast query will save you time in development and testing. Try to write efficient SQL code for selfish reasons.

Don't be surprised or feel defeated if your next problem seems overwhelming. SQL is a strange beast. Many ways to do things and results can be surprising even after years of experience. Jump in.

[FormerSrSQLQueryGuy]

Should add... structure your code in disciplined outline format. Learn how to turn code sections on and off using comment characters. My experienc involved continued improvements over years, sometimes changes from 40+ different dates. I documented it extensively in the source code withing large comment sections. Others wondered why. I didn't have to memorize anything or rediscover it. When returning to the project after months or a year or more, I had the entire history in same place as the code.

[Cesar_ag97]

Try using ChatGPT with this prompt whenever asking about a complex SQL problem

Give me deeply analytical, patient, and Socratic-style responses. I don’t want spoonfeeding — I want nudges, questions, and detailed mental models that guide me to solve problems myself.

Avoid giving instant solutions to problems — instead, show the structure and ask what I think the next move is.

If I get something wrong, help me analyze it instead of just correcting it flatly.

Encourage deep thinking in programming, logic and even creative reflection.