Most businesses and websites have databases that work behind the scenes and many of those databases rely on SQL. Structured Query Language is what is referred to as a specialized programming language in that it was designed for editing and querying data residing in relational database management systems.
Java's write-once-and-run-anywhere mantra says it all. This cross-platform, object-oriented programming language has become one of the most sought-after programming skills in the developer world. It's been around since 1995 and is still one of the most popular languages from a developer and an employer perspective.
C++, developed by Bjarne Strousup in 1983, is an enhancement of the programming language C. The addition of object-oriented programming has given this high-level language some low-level capabilities, making it a good multi-purpose language capable of building standalone applications as well as reusable code.
Object-oriented C# (pronounced "C Sharp") was developed by Microsoft as a multi-paradigm programming language that is fully compatible with Microsoft's .Net schema. Although it's used mainly on Windows, C# is designed as a cross-platform language.
Extensible Markup Language, or XML, is a markup language used to define document encoding that has gone on to become the default for many office productivity suites. Where HTML is about how information is displayed, XML is about transporting and storing data. The format is such that the code is readable by both humans and machines.
C is arguably the most widely used and currently the most popular programming language, according to the Tiobe Programming Community Index. A host of other programming languages have borrowed from this general purpose language including, C#, Python, Java, PHP, and Perl.
Larry Wall created Perl in 1987; it originally got its start as a general purpose Unix scripting language. It has a hodgepodge of features from C, shell script, AWK, and sed that is designed to allow developers to work more easily with text data.
Python is high-level object-oriented programming language that developers can use in many ways. Python is all about readability. Its uniform and streamlined syntax allows programmers to build concepts more quickly and with less code.