If you are searching for SQL or noSQL solutions, it is very difficult to decide among top SQL / noSQL Databases.
MySQL is the best for multi-document transactions, complex security, complex join, extreme compression.
NoSQL is good for linear scalability, high performance, schema flexibility.
But both depend on data need to manage 😉
Scalability
MySQL support master and slave approach for scaling (vertical scalability).
NoSQL supports horizontal scalability.
Vertical scalability is the ability to increase the capacity of existing hardware or software by adding resources – for example, adding processing power to a server to make it faster. On the other hand, horizontal scalability is the ability to connect multiple entities so that they work as a single logical unit.
Flexibility
SQL is the best for query flexibility, SQL supports both simple and complex queries.
MongoDB supports SQL query and indexes.
Down Time
NoSQL perform well for database size and server performance.
Transactions
SQL is king of transactions.
MongoDB and Redis support limited transactions.
Hosting
Every database solution need deployment, backups, monitoring, and performance tuning.
NoSQL are modern web-scale databases having qualities of non-relational, distributed, open-source and horizontally scalable database.