Horses for courses.The difference between someone who knows a computer language and can write a computer program, and an experienced, talented, skilled, developer is that the skilled developer is able to look at a particular use-case and determine the best (or at least a very good) option for how to implement it.
There are situations where a centralized database it the best choice. There are situations where a decentralized blockchain is the best choice. Anyone who blindly chooses one over the other without considering the benefits and requirements is a fool.
I couldn't agree more with above.
To even begin to compare you need at least understand both blockchain and sql. Without this understanding you will be trying to compare screwdriver with the hammer.