Learn the basic concepts and functions that you will need to make queries with the most popular data manipulating programming language, SQL.
This course is about SQL commands in the main. You will learn the basics of queries. This is a fundamental part of databases so it is definitly worth learning.
Learning the fundamentals of SQL is a good choice and puts a powerful tool at your fingertips. SQL is easy to learn as well as it has excellent documentations.
The most important fact about SQL that it is used in almost every speciality from software engineering to financial analysis, so understanding the concepts and basic language features can prove to be very marketable.