Type of Multi-modal NoSQL storage, works on top of MongoDB, Cassandra etc. Useful for modern applications like games and social networks where thousands of global replication is required.
Relational database using SQL server engine underneath. Database as a service. Easy to migrate on prem SQL server to the cloud. Managed, which means it is easy to replicate and scale.
Managed MySQL database, makes migration easier if on prem uses MySQL.
Managed PostgreSQL database, has better support for clusters and more complex server setups.
Most compatible with existing SQL server DB, almost no code change needed. Fully managed by Azure and always up to date.