MySQL is a free, open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). DO NOT USE this tag for other DBs such as SQL Server, SQLite etc. Those are different DBs which all use their own dialects of SQL to manage the data.

Structured Query Language (SQL) is a language for querying databases. Questions should include code examples, table structure, sample data, and a tag for the DBMS implementation (e.g. MySQL, PostgreSQL, Oracle, MS SQL Server, IBM DB2, etc.) being used. If your question relates solely to a specific DBMS (uses specific extensions/features), use that DBMS's tag instead. Answers to questions tagged with SQL should use ISO/IEC standard SQL.

R is a free, open-source programming language & software environment for statistical computing, bioinformatics, visualization & general computing. Please use minimal reproducible example(s) others can run using copy & paste. Show desired output. Use dput() for data & specify all non-base packages with library(). Don't embed pictures for data or code, use indented code blocks instead. For statistics questions, use https://stats.stackexchange.com.

Node.js is an event-based, non-blocking, asynchronous I/O runtime that uses Google's V8 JavaScript engine and libuv library. It is used for developing applications that make heavy use of the ability to run JavaScript both on the client, as well as on server side and therefore benefit from the re-usability of code and the lack of context switching.

React is a JavaScript library for building user interfaces. It uses a declarative, component-based paradigm and aims to be both efficient and flexible.

An array is an ordered linear data structure consisting of a collection of elements (values, variables, or references), each identified by one or more indexes. When asking about specific variants of arrays, use these related tags instead: [vector], [arraylist], [matrix]. When using this tag, in a question that is specific to a programming language, tag the question with the programming language being used.

C is a general-purpose programming language used for system programming (OS and embedded), libraries, games and cross-platform. This tag should be used with general questions concerning the C language, as defined in the ISO 9899 standard (the latest version, 9899:2018, unless otherwise specified — also tag version-specific requests with c89, c99, c11, etc). C is distinct from C++ and it should not be combined with the C++ tag absent a rational reason.

ASP.NET is a Microsoft web application development framework that allows programmers to build dynamic web sites, web applications and web services. It is useful to use this tag in conjunction with the project type tag e.g. [asp.net-mvc], [asp.net-webforms], or [asp.net-web-api]. Do NOT use this tag for questions about ASP.NET Core - use [asp.net-core] instead.

JSON (JavaScript Object Notation) is a serializable data interchange format intended to be machine and human readable. Do not use this tag for native JavaScript objects or JavaScript object literals. Before you ask a question, validate your JSON using a JSON validator such as JSONLint (https://jsonlint.com).

Ruby on Rails is an open source full-stack web application framework written in Ruby. It follows the popular MVC framework model and is known for its "convention over configuration" approach to application development.

Do NOT use for questions about .NET 5+ or .NET Core - use [.net-core] instead. The .NET framework is a software framework designed mainly for the Microsoft Windows operating system. It includes an implementation of the Base Class Library, Common Language Runtime (commonly referred to as CLR), Common Type System (commonly referred to as CTS) and Dynamic Language Runtime. It supports many programming languages, including C#, VB.NET, F# and C++/CLI.