What is SQL? Where it use? Why I need to learn this?

Question

Plz anyone explain SQL in Detail.

Answer 1

What is SQL:
SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system, or for stream processing in a relational data stream management system. 
Where it use:
SQL is used to communicate with a database. According to ANSI (American National Standards Institute), it is the standard language for relational database management systems. SQL statements are used to perform tasks such as update data on a database, or retrieve data from a database
Why i need to learn this:
To communicate with database.

I hope it helps you

Answer 2

SQL is for database management. You can use it in excel, for example. One way you might need it is to manage large amounts of data, like names and email adresses. or any data you have collected or created