Distributed SQL Database

• Distributed SQL

Scale your SQL Database across 100s of nodes.Apache Ignite comes with ANSI-99 compliant, horizontally scalable and fault-tolerant distributed SQL database.
As an​ SQL database, Ignite supports all DML commands including SELECT, UPDATE, INSERT, and DELETE queries. It also implements a subset of DDL commands relevant for distributed systems.
https://apacheignite.readme.io/docs/distributed-sql

• TRADITIONAL RELATIONAL SQL DATABASES

like Oracle and Microsoft SQL Server are great for on-premises, single data center environments, but fail to adapt to the more distributed, less predictable, and higher in volume workloads found in today’s enterprise.
NOSQL SOLUTIONS
like MongoDB, Couchbase, and DataStax solve for on-demand scale and continuous availability needs, but force organizations to rewrite SQL-based applications, resulting in the loss of the data consistency that transactional systems require
NEWSQLPRODUCTS
such as VoltDB, Clustrix, and MemSQL maintain SQL as they scale, but are often limited to highly specialized use cases such as streaming or batch analytic applications

In short, if you are looking to retain your traditional SQL database benefits and gain new cloud efficiencies, then a distributed SQL database is the right option to consider.
https://www.nuodb.com/digging-distributed-sql

• Apache Ignite™ is a memory-centric distributed database, caching, and processing platform for

transactional, analytical, and streaming workloads delivering in-memory speeds at petabyte scale
https://ignite.apache.org/

• F1: A Distributed SQL Database That Scales

F1 is a hybrid database that combines high availability, the scalability of NoSQL systems like Bigtable, and the consistency and usability of traditional SQL databases.
https://ai.google/research/pubs/pub41344

• Actordb

Distributed SQL database with linear scalability
http://www.actordb.com/

• NewSQL is a class of modern relational database management systems that seek to provide the same scalable performance of NoSQL systems for online transaction processing (OLTP) read-write workloads while still maintaining the ACID guarantees of a traditional database system.

https://en.wikipedia.org/wiki/NewSQL