Tables, rows, and columns

Inside each table in a database, information is organized into rows and columns. A row is a single record, such as one person, one order, or one product. A column is a type of information stored for every record, such as a name, a price, or a date. A cell is a single value, such as the name 'John' or the date 2025-10-12. Together, the rows and columns form a grid of cells much like a spreadsheet. You can look across a row to see all the details for one record, or down a column to see that type of information for many records.

About This Interactive Section

This section is part of the Query Structure: Beginner lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

How DataDriven Lessons Work

DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.