SQL and NoSQL represent two fundamental database approaches. SQL (Structured Query Language) databases are relational, using tables with predefined schemas. They excel in maintaining data consistency (ACID properties) and handling complex queries with clear relationships, making them ideal for traditional business applications like financial systems.

NoSQL (Not Only SQL) databases are non-relational, offering flexible schemas to store diverse data formats like documents, key-value pairs, or graphs. They prioritize scalability (horizontal scaling) and availability (BASE properties), making them perfect for handling large volumes of unstructured or rapidly changing data, common in web applications, social media, and big data analytics. The choice depends on data structure, scalability needs, and consistency requirements.