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Josep Ferrer @rfeers.bsky.social · 10d

START LEARNING

𝗦𝗤𝗟

RIGHT NOW!!

www.databites.tech/p/how-to-ac...

How to Actually Get Started with SQL

CS16 - A clear (and human) guide to get started without drowning

www.databites.tech

Josep Ferrer @rfeers.bsky.social · 10d

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Then join the DataBites newsletter to get weekly issues about Data Science and more! 🧩

👉🏻 databites.tech

Josep Ferrer @rfeers.bsky.social · 10d

If you like this thread, go check the original article‼️

www.databites.tech/p/how-to-ac...

How to Actually Get Started with SQL

CS16 - A clear (and human) guide to get started without drowning

www.databites.tech

1

Josep Ferrer @rfeers.bsky.social · 10d

15. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝗤𝗟 𝗧𝗲𝗰𝗵𝗻𝗶𝗾𝘂𝗲𝘀
For seasoned users, explore sophisticated SQL features:
• Windows Functions, Recursive Queries
• Pivot/Unpivot Operations, Common Table Expressions (CTE)

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Josep Ferrer @rfeers.bsky.social · 10d

The two final steps is learning how to craft better and more optimized SQL queries.

14. 𝗣𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻
Techniques to enhance the efficiency of your queries:
• Query Analysis, Optimizing JOINS, Reducing Subqueries

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Josep Ferrer @rfeers.bsky.social · 10d

13. 𝗗𝗮𝘁𝗮 𝗜𝗻𝘁𝗲𝗴𝗿𝗶𝘁𝘆 𝗮𝗻𝗱 𝗦𝗲𝗰𝘂𝗿𝗶𝘁𝘆
Now that you are here, I strongly recommend you get familiar with security best practices. Maintain the security and integrity of your database:
• Using GRANT and REVOKE
• Database Security Best Practices

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Josep Ferrer @rfeers.bsky.social · 10d

Now you should focus on crafting better queries by leveraging indexes and following best security practices 💥

12. 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗜𝗻𝗱𝗲𝘅𝗲𝘀
Indexes improve query performance:
• Unique, Clustered, and Non-Clustered Indexes

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Josep Ferrer @rfeers.bsky.social · 10d

Once a result is good, you might want to create a view!
11. 𝗪𝗼𝗿𝗸𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗩𝗶𝗲𝘄𝘀
Views can simplify complex queries:
• Creating, Modifying, and Dropping Views

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Josep Ferrer @rfeers.bsky.social · 10d

Now you should understand advanced syntax like specific functions and new ways of merging data like UNION.

10. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝘆𝗻𝘁𝗮𝘅
Explore more complex SQL operations:
• UNION, INTERSECT, EXCEPT
• CASE, COALESCE, and Functions for NULL Handling

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Josep Ferrer @rfeers.bsky.social · 10d

Your SQL skills here are already really good!! 🙌🏻
But learning must go on…

9. 𝗟𝗲𝘃𝗲𝗿𝗮𝗴𝗶𝗻𝗴 𝗦𝘂𝗯𝗾𝘂𝗲𝗿𝗶𝗲𝘀
As queries keep getting more complex, you need to create subqueries.
• Nested and Correlated Subqueries
• EXISTS and NOT EXISTS

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Josep Ferrer @rfeers.bsky.social · 10d

Our data will usually be spread across many different tables, this is why being able to merge data from different sources is crucial in SQL.

8. 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗝𝗢𝗜𝗡𝘀
JOINs are critical for combining data from multiple tables:
• INNER, LEFT, RIGHT, and FULL OUTER JOINs

1

Josep Ferrer @rfeers.bsky.social · 10d

If you like this thread, go check the original article‼️

www.databites.tech/p/how-to-ac...

How to Actually Get Started with SQL

CS16 - A clear (and human) guide to get started without drowning

www.databites.tech

1

Josep Ferrer @rfeers.bsky.social · 10d

👉🏻 This will be one of the most important steps when creating KPIs and specific metrics.

7. 𝗘𝗻𝗳𝗼𝗿𝗰𝗶𝗻𝗴 𝗖𝗼𝗻𝘀𝘁𝗿𝗮𝗶𝗻𝘁𝘀
Ensure data integrity through constraints:
• PRIMARY KEY, FOREIGN KEY, UNIQUE
• NOT NULL and CHECK Constraints

1

Josep Ferrer @rfeers.bsky.social · 10d

Now you should keep getting better with SQL programming language 💥

6. 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱𝗶𝗻𝗴 𝗔𝗴𝗴𝗿𝗲𝗴𝗮𝘁𝗶𝗼𝗻
Aggregate functions are powerful tools for summarizing data:
• SUM, AVG, COUNT, MAX, MIN

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Josep Ferrer @rfeers.bsky.social · 10d

5. 𝗗𝗮𝘁𝗮 𝗠𝗮𝗻𝗶𝗽𝘂𝗹𝗮𝘁𝗶𝗼𝗻
Get hands-on with inserting, updating, and deleting data:
• INSERT, UPDATE, DELETE Commands

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Josep Ferrer @rfeers.bsky.social · 10d

Already proficient with basic commands?

Now it’s turn to understand how to manage databases with the following two steps:

4. 𝗗𝗮𝘁𝗮 𝗗𝗲𝗳𝗶𝗻𝗶𝘁𝗶𝗼𝗻
Learn how to structure and manage your databases with:
• CREATE, ALTER, DROP Statements

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Josep Ferrer @rfeers.bsky.social · 10d

3. 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗕𝗮𝘀𝗶𝗰 𝗞𝗲𝘆𝘄𝗼𝗿𝗱𝘀
The first real step is to familiarize yourself with the commands that form the backbone of SQL querying:

• SELECT, FROM, WHERE
• ORDER BY and LIMIT Clauses

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Josep Ferrer @rfeers.bsky.social · 10d

2. 𝗘𝘅𝗽𝗹𝗼𝗿𝗶𝗻𝗴 𝗗𝗮𝘁𝗮 𝗧𝘆𝗽𝗲𝘀
Once you have a clear image of SQL, you should understand the core data types you will be working with 👇🏻

• Integers, Decimals, and Booleans
• Character Types: CHAR and VARCHAR
• Dates and Binary Data

1

Josep Ferrer @rfeers.bsky.social · 10d

If you like this thread, go check the original article‼️

www.databites.tech/p/how-to-ac...

How to Actually Get Started with SQL

CS16 - A clear (and human) guide to get started without drowning

www.databites.tech

1

Josep Ferrer @rfeers.bsky.social · 10d

1. 𝗟𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝘁𝗵𝗲 𝗕𝗮𝘀𝗶𝗰𝘀
Before diving deep, it's essential to grasp what is SQL.

Begin with:
• What is a Relational Database?
• Comparing SQL and NoSQL Databases
• Understanding SQL Syntax and Basic Commands

1

Josep Ferrer @rfeers.bsky.social · 10d

🚀 New to SQL?

Then here’s a roadmap to get you started in 2025, step-by-step! 🧵👇

(Don't forget to bookmark for later!! 😉 )

1

Josep Ferrer @rfeers.bsky.social · 17d

Did you like this post?

Then join the DataBites newsletter to get weekly issues about Data Science and more! 🧩

👉🏻 databites.tech

Josep Ferrer @rfeers.bsky.social · 17d

This roadmap covers everything you need to go from a beginner to an advanced Python programmer! 🌱

1

Josep Ferrer @rfeers.bsky.social · 17d

17. 𝗗𝗲𝘃𝗢𝗽𝘀 𝗮𝗻𝗱 𝗗𝗲𝗽𝗹𝗼𝘆𝗺𝗲𝗻𝘁
Integrate Python into DevOps practices to deploy and scale your applications. Understanding CI/CD, Docker, and cloud deployment will make your skills industry-ready.

1

Josep Ferrer @rfeers.bsky.social · 17d

16. 𝗧𝗲𝘀𝘁𝗶𝗻𝗴
Testing is essential for reliable software! Learn the basics of Doctest, Nose, Pytest, and Unittest. These tools help ensure that your code works as expected.

1