What's about all the SQLs

Question

I didn't know how to explain in title but what I truly wanna ask is there are lot of SQL languages ( MySQL, prosql, SQL etc. )
What is different above this all?

Answer 1

There is one SQL standard, acknowledged by both the ANSI and ISO organizations.

But there are many different database engines, RDBMS software which implement this standard, such as Oracle SQL, MySql, Postgresql, Microsoft SQL Server, SQLite and others. Each of these database engines have their own unique flavor or "dialect", which means that most of the time they conform with the common standard, but occasionally they do things differently and they have extra features or special functions and keywords that are really unique to that database.

This is partly due to historical reasons, because the database vendors were innovating more quickly than how the standardization happened.

https://learnsql.com/blog/history-of-sql-standards/