I need to know the substantive differences and similarities between the major database vendors (Oracle, Microsoft SQL, Amazon, MongoDB) I would like…

I need to know the substantive differences and similarities between the major database vendors (Oracle, Microsoft SQL, Amazon, MongoDB) I would like to know how someone chooses between them. What are the differences between SQL and NOSQL vendors and how are they used in the IT industry. Are any of them specialized or better for certain tasks or data? Also I would like to know their relative popularity. Which is used most frequently?