SQL syntax is close to natural language, with a low learning threshold and the bonus of first-mover advantage, it soon became popular between database manufacturers and users. After years of development, SQL has become the most widely used and most mature structured data computing language.
However, SQL must work based on RDB, and there is no RDB in many scenarios, such as encountering CSV \ restful JSON \ MongoDB and other data sources or performing mixed calculations between these data sources, such as CSV and XLS. In these scenarios, many people will choose to hard code algorithms in high-level languages such as Java or C#, etc., which requires writing lengthy underlying functions from scratch, and the execution efficiency is difficult to guarantee.