TO_BASE64() / FROM_BASE64()

Basic Concepts Base64 solves a fundamental problem: binary data contains bytes that are not valid text characters. Attempting to store raw binary in a text field corrupts the data. Base64 transforms binary into safe text that survives any text processing. The = characters at the end are padding. Base64 works in groups of 4 characters, and padding fills incomplete groups. The encoded result contains only letters, numbers, plus, slash, and equals. Encoding & Decoding Decoding Base64 to Text Best Practices Many APIs require Base64-encoded payloads or return Base64-encoded responses: Log tables often store API responses in Base64 to handle binary content safely. This query decodes them for analysis. The same pattern works for request bodies, file contents, or any binary data stored as text. Ba

About This Interactive Section

This section is part of the String Functions: Advanced 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.

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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.