Tools are predominantly created using either Excel or Qlikview.
Typically used as prototypes to test and finalize requirements and of course for calculation-intensive applications.
Excel applications can also serve as a front-end to one or more database systems and for all sorts of programs where development speed and low costs are key.
Excel-based software is also ideal for build-it-yourself projects, as the learning curve is not as steep as with other tools or programming languages.
Excel applications often include macros and custom functions in VBA.
Most frequently used tools are Access (Microsoft) and FileMaker Pro. These small databases are ideal for small businesses consisting of 1-20 people.
Typical applications include: ERP systems, Customer management software and product or services management.
MySQL, recently Postgres and some rare occasions SQL Server (by Microsoft). These systems reside on a server and are commonly accessed via a browser, either on the company's own Intranet or the Internet.
Often companies don't really know what they want until they see. here is where protoypes come in.
Some prototypes are developed with Excel. Others, requiring more computing power are created with Python, PHP, Matlab, on rare occasions C or a combination of these.
A web application is just a normal program which is accessed by a web browser. These applications are available either via a company's intranet or are made available (with login and password) on the Internet.