It is worth mentioning that there are some data-process heavy work that can be done much faster and more efficiently in SQL.

Real life example for a regulatory batch job:

6 tomcat servers + 1 RDS. 30X lines of code + UTs in java. 30+ minutes time.

In SQL No tomcat servers + 1 RDS instance. 1X lines of code(SQL) + UTs (in java). 3+ minutes

Here is a good book on it: https://www.amazon.co.uk/Relational-Database-Programming-Set...