Thread by @Sachintukumar

Are you completely new to SQL and do not know where to start?

Here is a simple concept roadmap for learning SQL as a complete beginner:

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1. 𝐋𝐞𝐚𝐫𝐧 𝐭𝐡𝐞 𝐛𝐚𝐬𝐢𝐜𝐬:

- Primary Key vs Foreign Key
- Data Types
- Database diagrams
- Tables
- Records and Fields
- Naming standards for tables and fields

2. 𝐑𝐞𝐭𝐫𝐢𝐞𝐯𝐢𝐧𝐠 𝐃𝐚𝐭𝐚 𝐰𝐢𝐭𝐡 𝐒𝐄𝐋𝐄𝐂𝐓:

- Learn how to write SELECT 𝘤𝘰𝘭𝘶𝘮𝘯(𝘴) FROM 𝘵𝘢𝘣𝘭𝘦
- Combine with other keywords: WHERE, ORDER BY & LIMIT
- Learn how to use arithmetic operators in SELECT statement
- Retrieve unique values with DISTINCT keyword

3. 𝐋𝐞𝐚𝐫𝐧 𝐭𝐨 𝐉𝐎𝐈𝐍 𝐭𝐚𝐛𝐥𝐞𝐬

- Learn the four basic JOINS (INNER JOIN, FULL OUTER JOIN, LEFT JOIN, RIGHT JOIN)
- Study the Venn Diagrams behind each type of JOIN
- Understand relationship types (one-to-one, one-to-many, many-to-many)
- JOIN multiple tables

4. 𝐋𝐞𝐚𝐫𝐧 𝐃𝐚𝐭𝐚 𝐀𝐠𝐠𝐫𝐞𝐠𝐚𝐭𝐢𝐨𝐧 

- GROUP BY statement
- SUM, AVG, COUNT, MAX, MIN, ect....
- Learn the difference between WHERE vs HAVING

5. 𝐋𝐞𝐚𝐫𝐧 𝐦𝐨𝐫𝐞 𝐚𝐝𝐯𝐚𝐧𝐜𝐞𝐝 𝐜𝐨𝐧𝐜𝐞𝐩𝐭𝐬

- Learn how to use CASE-WHEN statement
- Common Table Expressions (CTEs)
- Write subqueries in SELECT, WHERE & FROM clauses to retrieve data based on condition or calculation
- Write subqueries in tandem with Aggregate Fn

The concepts in the above roadmap will be enough #SQL knowledge required for most entry-level data analyst reporting positions. More SQL knowledge would be required for an entry-level database developer or data engineer role

Source - Drew Zeimetz

#DataScience #MachineLearning

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