Structured Query Language.
DynamoDB is used when you need a fast, scalable, and highly available NoSQL database for workloads that don’t require complex relational queries.
Amazon DynamoDB is also very popular, especially for NoSQL, high-scale use cases.
Aurora is a high-performance, highly available, and scalable relational database built by AWS, compatible with MySQL and PostgreSQL.
RDS is a broader managed DB service supporting multiple engines with standard performance.