Guided Notes
Introduction to SQL
Databases, tables and schemas, plus SELECT, filtering, and aggregation basics.
What is SQL?
Slide 1 / 5SQL (Structured Query Language) is how you ask a relational database for data. Nearly every company stores its customers, orders, and transactions in databases, and SQL is the common language for reading them — in MySQL, PostgreSQL, SQL Server, SQLite, and cloud warehouses like Google BigQuery.
A query describes the result you want, not the steps to get it. The database works out how to find the rows efficiently.