How to decode URL-encoded strings in ClickHouse ®

URL-encoded strings are common in web data, where special characters are converted to percent signs followed by hexadecimal codes, like %20 for spaces. ClickHouse's decodeURLComponent function reverses this encoding, transforming strings back into readable text, and is particularly useful in web analytics and API logs. The function is designed to handle standard percent-encoding and edge cases like double encoding and Unicode sequences. It can be used on individual strings or entire columns and is optimized for performance on large datasets through the use of materialized views and LowCardinality encoding. Strategies for handling URL decoding include replacing plus signs with spaces and detecting double encoding. The function is integrated into a broader data processing framework using Tinybird, which allows for real-time URL decoding, aggregation, and querying through API endpoints, providing a scalable solution for high-throughput applications. Additionally, Tinybird's managed ClickHouse service offers advantages such as fast deployments, built-in API generation, and data-as-code workflows, simplifying the development and maintenance of URL processing pipelines.