Google Cloud Platform offers a number of different fully managed database services from RDBMS to NoSQL for different use cases.
Use Case
Cloud SQL
Managed, highly available RDBMS with MySQL, PostgreSQL, and SQL Server.
Traditional RDBMS, enterprise/business applications, web applications.
Horizontally scalable, globally/regionally distributed, highly available, strongly consistent RDBMS.
Mission critical applications that requires 99.999% SLA. Regionally or globally available applications that needs fast data access. Large data sizes that no longer fit in traditional RDBMS.
Managed NoSQL Document-oriented database.
Applications with data structure that's fast changing, or document oriented.