Structured Query Language (SQL) is the backbone of data analysis, data engineering, and business intelligence. Whether you're querying a relational database, building ETL pipelines, or exploring datasets in Power BI, SQL is the language that lets you interact with data efficiently and precisely. This cheat sheet is designed to be your quick-access reference for the most commonly used SQL commands, clauses, functions, and patterns. It’s ideal for beginners who want to learn fast, and for experienced analysts who need a refresher or a compact guide. 📌 What Is SQL? SQL (Structured Query Language) is a domain-specific language used to manage and manipulate relational databases. It allows users to: Retrieve data ( SELECT ) Insert new records ( INSERT ) Update existing data ( UPDATE ) Delete records ( DELETE ) Create and modify tables ( CREATE , ALTER ) Control access and permissions ( GRANT , REVOKE ) SQL is supported by most relational database systems, including: Microsoft SQL Serv...
Practical training for data analysts and rational investors. Guides on SQL, data analysis, ETL, and personal finance to make data-driven decisions.