Build the foundation for your entire Data Science journey.
Module Objectives:
Module 1.1 lays the foundation for the entire Data Science journey. You will understand how enterprise data is organized, why SQL is important, and why every data role requires this skill. The goal is to help you view data "the right way," know how to read ERD, and master basic SQL—a stepping stone to analyze data at a higher level.
What You Will Achieve After This Module:
- Read and understand ERD like a professional Data Analyst.
- Write SQL queries proficiently from basic to intermediate level.
- Know how to analyze real data using SQL without Excel.
- Master data processing thinking: filter – group – join – aggregate.
- Confidently enter subsequent modules like Exploratory Data Analysis and Machine Learning.
Career Value:
- SQL is a mandatory skill in every JD related to data.
- Mastering SQL helps you process large datasets that Excel cannot handle.
- You have a solid foundation to pass technical tests for Data Analyst / BI Analyst / Data Scientist positions.
1 — INTRODUCTION TO DATABASE
- Database is a large, fast, and more reliable data storage system than Excel/CSV.
- DBMS (MySQL, PostgreSQL, SQL Server…) supports: data management & security, user permissions, concurrent query processing, ensuring data consistency.
- Basic data structure: Table — Column — Row — Schema, illustrated with real enterprise models.
- ERD describes Database structure and relationships between tables.
2 — BASIC SQL
You will learn and practice:
- Syntax SELECT – FROM – WHERE
- GROUP BY – HAVING – ORDER BY
- DISTINCT – LIMIT – OFFSET
- SQL Order of Execution: How SQL processes queries through a pipeline.
- Data Types: text, numeric, datetime, boolean.
- Operators: LIKE, BETWEEN, IN, AND/OR,…
- Ask questions and answer with real data using only SQL.
3 — INTERMEDIATE SQL
You will expand to more advanced techniques:
- INNER JOIN, LEFT JOIN, FULL JOIN
- JOIN multiple tables in one query
- Handling NULL
- Aggregate Functions: COUNT, SUM, AVG, MIN, MAX
- Understanding how enterprise databases work — a major advantage in interviews.
- Subqueries in SELECT/WHERE/FROM
- Capable of analyzing real-world problems: best-selling products, returning customers, revenue over time…
4 — ADVANCED SQL
You will approach professional data analysis thinking:
- CTE (WITH) to break down complex problems
- UNION & CASE WHEN
- SQL problem-solving thinking: Filter → Aggregate → Join → Subquery
- Common mistakes and how to avoid them:
- Random use of SELECT *, wrong JOIN relationships, missing columns in GROUP BY, misunderstanding NULL.
- You will be equipped with enterprise-standard SQL thinking.
EXAM – INTRODUCTION TO DATABASE & SQL
- Know how to read and analyze ERD.
- Write complete SQL queries from basic to intermediate level.
- Independently process data without relying on Excel.
- Understand how to apply SQL in an enterprise context.
So stay motivated, stay curious, and most importantly, keep practicing. The future belongs to those who can harness the power of data, and with SQL, you will be well on your way to doing just that.
Take your time, be patient, and don't hesitate to ask for help when needed.
Welcome to the Introduction to Database & SQL module, and happy learning! 🚀