Hi,
SQL is a programming language that allows programmers to easily manage the data that is held in database systems. It is also required to know if you are going to learn PL/SQl and/or become a Database Administrator. SQL is taught in several different flavors including Oracle, Microsoft and PostgreSQL.
You can start with GogoTraining's 'Entry Level SQL Programming'. Their
SQL server training course include 3 options:
1) Introduction for Programming and Coding for Everyone with Javascipt
2) Oracle 11g/12c: Introduction to SQL
3) Oracle 11g/12c: Advanced SQL
SQL is used every place there is a database of information that needs to be managed so you can imagine that there are many, many jobs available.
The average salary for an experienced SQL Progammer is $102,000.
Hope this helps.