Create Tables and Query Data | DDL, SELECT, WHERE & ORDER BY

Description:
This is Part 1 of a three-part SQL series designed to give you a practical understanding of SQL without weeks of confusing lessons.

We begin with the essential vocabulary—databases, schemas, tables, rows, columns, data types and constraints—before moving into real SQL.

You’ll learn how to:
- Create and modify tables with DDL
- Understand CREATE TABLE and ALTER TABLE
- Read the structure of a SQL query
- Select and rename columns
- Filter records with WHERE
- Sort and limit results
- Create conditional categories with CASE
- Handle missing values correctly with NULL and IS NULL
- Turn a business question into a clean SQL query

All examples use the same practice dataset, so you can follow the progression from defining the data to querying it.

Practice files and SQL exercises: https://github.com/david-ikenna-ezekiel/thedatasignal/tree/main/sql-masterclass

Chapters
00:00 From a business question to SQL
00:22 Setup and essential SQL terminology
03:21 DDL: Creating and modifying tables
05:07 How a SQL query works
06:08 SELECT, WHERE, ORDER BY and CASE
09:20 Final query, NULL handling and recap

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