Structured Query Language (SQL) is a domain-specific language used for managing and manipulating relational databases. It provides a standardized way to communicate with databases, allowing users to perform various operations on data, such as querying, inserting, updating, and deleting records, as well as creating and modifying database structures.

SQL is used by developers, database administrators, and data analysts to interact with databases. It consists of several categories of statements:

  1. Data Query Language (DQL): Used to retrieve data from one or more tables using the SELECT statement.
  2. Data Manipulation Language (DML): Used to manipulate data stored in a database using statements like INSERT, UPDATE, and DELETE.
  3. Data Definition Language (DDL): Used to define and manage the structure of the database, including statements like CREATE, ALTER, and DROP.
  4. Data Control Language (DCL): Used to manage permissions and security within the database, including statements like GRANT and REVOKE.
  5. Transaction Control Language (TCL): Used to manage transactions within the database, including statements like COMMIT, ROLLBACK, and SAVEPOINT.

SQL is not specific to any particular database system; it is supported by most relational database management systems (RDBMS). Some popular RDBMS that use SQL include MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server, and SQLite.

SQL syntax and features may vary slightly between different database systems, but the core concepts and principles remain consistent. It’s a fundamental skill for anyone working with databases and data management.