Josep Ferrer
@rfeers.bsky.social
Data Scientist & Tech Writer KDnuggets, DataCap, TDS & Medium
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October 22, 2025 at 10:35 AM
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15. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝗤𝗟 𝗧𝗲𝗰𝗵𝗻𝗶𝗾𝘂𝗲𝘀
For seasoned users, explore sophisticated SQL features:
• Windows Functions, Recursive Queries
• Pivot/Unpivot Operations, Common Table Expressions (CTE)
For seasoned users, explore sophisticated SQL features:
• Windows Functions, Recursive Queries
• Pivot/Unpivot Operations, Common Table Expressions (CTE)
October 22, 2025 at 10:35 AM
15. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝗤𝗟 𝗧𝗲𝗰𝗵𝗻𝗶𝗾𝘂𝗲𝘀
For seasoned users, explore sophisticated SQL features:
• Windows Functions, Recursive Queries
• Pivot/Unpivot Operations, Common Table Expressions (CTE)
For seasoned users, explore sophisticated SQL features:
• Windows Functions, Recursive Queries
• Pivot/Unpivot Operations, Common Table Expressions (CTE)
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
14. 𝗣𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻
Techniques to enhance the efficiency of your queries:
• Query Analysis, Optimizing JOINS, Reducing Subqueries
October 22, 2025 at 10:35 AM
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
14. 𝗣𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻
Techniques to enhance the efficiency of your queries:
• Query Analysis, Optimizing JOINS, Reducing Subqueries
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
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
October 22, 2025 at 10:35 AM
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
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
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
12. 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗜𝗻𝗱𝗲𝘅𝗲𝘀
Indexes improve query performance:
• Unique, Clustered, and Non-Clustered Indexes
October 22, 2025 at 10:35 AM
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
12. 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗜𝗻𝗱𝗲𝘅𝗲𝘀
Indexes improve query performance:
• Unique, Clustered, and Non-Clustered Indexes
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
11. 𝗪𝗼𝗿𝗸𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗩𝗶𝗲𝘄𝘀
Views can simplify complex queries:
• Creating, Modifying, and Dropping Views
October 22, 2025 at 10:35 AM
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
11. 𝗪𝗼𝗿𝗸𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗩𝗶𝗲𝘄𝘀
Views can simplify complex queries:
• Creating, Modifying, and Dropping Views
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
10. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝘆𝗻𝘁𝗮𝘅
Explore more complex SQL operations:
• UNION, INTERSECT, EXCEPT
• CASE, COALESCE, and Functions for NULL Handling
October 22, 2025 at 10:35 AM
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
10. 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗦𝘆𝗻𝘁𝗮𝘅
Explore more complex SQL operations:
• UNION, INTERSECT, EXCEPT
• CASE, COALESCE, and Functions for NULL Handling
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
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
October 22, 2025 at 10:35 AM
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
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
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
8. 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗝𝗢𝗜𝗡𝘀
JOINs are critical for combining data from multiple tables:
• INNER, LEFT, RIGHT, and FULL OUTER JOINs
October 22, 2025 at 10:35 AM
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
8. 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗝𝗢𝗜𝗡𝘀
JOINs are critical for combining data from multiple tables:
• INNER, LEFT, RIGHT, and FULL OUTER JOINs
👉🏻 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
7. 𝗘𝗻𝗳𝗼𝗿𝗰𝗶𝗻𝗴 𝗖𝗼𝗻𝘀𝘁𝗿𝗮𝗶𝗻𝘁𝘀
Ensure data integrity through constraints:
• PRIMARY KEY, FOREIGN KEY, UNIQUE
• NOT NULL and CHECK Constraints
October 22, 2025 at 10:35 AM
👉🏻 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
7. 𝗘𝗻𝗳𝗼𝗿𝗰𝗶𝗻𝗴 𝗖𝗼𝗻𝘀𝘁𝗿𝗮𝗶𝗻𝘁𝘀
Ensure data integrity through constraints:
• PRIMARY KEY, FOREIGN KEY, UNIQUE
• NOT NULL and CHECK Constraints
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
6. 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱𝗶𝗻𝗴 𝗔𝗴𝗴𝗿𝗲𝗴𝗮𝘁𝗶𝗼𝗻
Aggregate functions are powerful tools for summarizing data:
• SUM, AVG, COUNT, MAX, MIN
October 22, 2025 at 10:35 AM
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
6. 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱𝗶𝗻𝗴 𝗔𝗴𝗴𝗿𝗲𝗴𝗮𝘁𝗶𝗼𝗻
Aggregate functions are powerful tools for summarizing data:
• SUM, AVG, COUNT, MAX, MIN
5. 𝗗𝗮𝘁𝗮 𝗠𝗮𝗻𝗶𝗽𝘂𝗹𝗮𝘁𝗶𝗼𝗻
Get hands-on with inserting, updating, and deleting data:
• INSERT, UPDATE, DELETE Commands
Get hands-on with inserting, updating, and deleting data:
• INSERT, UPDATE, DELETE Commands
October 22, 2025 at 10:35 AM
5. 𝗗𝗮𝘁𝗮 𝗠𝗮𝗻𝗶𝗽𝘂𝗹𝗮𝘁𝗶𝗼𝗻
Get hands-on with inserting, updating, and deleting data:
• INSERT, UPDATE, DELETE Commands
Get hands-on with inserting, updating, and deleting data:
• INSERT, UPDATE, DELETE Commands
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
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
October 22, 2025 at 10:35 AM
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
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
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
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
October 22, 2025 at 10:35 AM
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
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
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
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
October 22, 2025 at 10:35 AM
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
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. 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
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
October 22, 2025 at 10:35 AM
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
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
Did you like this post?
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Then join the DataBites newsletter to get weekly issues about Data Science and more! 🧩
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October 15, 2025 at 10:23 AM
Did you like this post?
Then join the DataBites newsletter to get weekly issues about Data Science and more! 🧩
👉🏻 databites.tech
Then join the DataBites newsletter to get weekly issues about Data Science and more! 🧩
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This roadmap covers everything you need to go from a beginner to an advanced Python programmer! 🌱
October 15, 2025 at 10:23 AM
This roadmap covers everything you need to go from a beginner to an advanced Python programmer! 🌱
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.
Integrate Python into DevOps practices to deploy and scale your applications. Understanding CI/CD, Docker, and cloud deployment will make your skills industry-ready.
October 15, 2025 at 10:23 AM
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.
Integrate Python into DevOps practices to deploy and scale your applications. Understanding CI/CD, Docker, and cloud deployment will make your skills industry-ready.
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.
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.
October 15, 2025 at 10:23 AM
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.
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.