**SQL** (Structured Query Language) is a domain-specific [[Programming language|programming language]] designed for managing and manipulating data held in [[Relational database|relational databases]]. Standardized by the [[American National Standards Institute|American National Standards Institute]] (ANSI) in 1986 and subsequently by the [[International Organization for Standardization|International Organization for Standardization]] (ISO), SQL provides a declarative syntax for defining data structures, querying and updating records, controlling access permissions, and managing [[Database transaction|transactions]]. It is the most widely used database language in the world and is supported, with varying extensions and dialects, by virtually all major [[Relational database management system|relational database management systems]] (RDBMS) including [[PostgreSQL]], [[MySQL]], [[Microsoft SQL Server|SQL Server]], [[Oracle Database|Oracle]], [[SQLite]], and [[IBM Db2|IBM DB2]]. SQL was developed at [[IBM]] in the early 1970s by [[Donald D. Chamberlin|Donald Chamberlin]] and [[Raymond F. Boyce|Raymond Boyce]], drawing on the [[Relational model|relational model]] formalized by [[Edgar F. Codd]]. Originally called SEQUEL (Structured English Query Language), the language was designed to provide a human-readable interface for querying relational data organized into [[Table (database)|tables]] of rows and columns. IBM's initial implementation, System R, demonstrated the practical viability of the relational approach, and commercial relational database products based on SQL began appearing in the late 1970s and early 1980s. The ANSI SQL standard has been revised numerous times, with major versions including SQL-92, SQL:1999, SQL:2003, SQL:2008, SQL:2011, and SQL:2016 progressively adding support for features such as [[Join (SQL)|complex joins]], [[Stored procedure|stored procedures]], [[Trigger (databases)|triggers]], [[Window function (SQL)|window functions]], [[Common table expression|common table expressions]] (CTEs), [[XML]], [[JSON]], and [[Temporal database|temporal data]]. SQL is organized into several functional sublanguages. The **[[Data Definition Language|Data Definition Language]]** (DDL) encompasses statements such as `CREATE`, `ALTER`, and `DROP` for defining and modifying database [[Database schema|schema]] objects. The **[[Data Manipulation Language|Data Manipulation Language]]** (DML) includes `SELECT`, `INSERT`, `UPDATE`, and `DELETE` for querying and modifying data. The **[[Data Control Language|Data Control Language]]** (DCL) provides `GRANT` and `REVOKE` statements for managing access permissions. The **[[Transaction Control Language|Transaction Control Language]]** (TCL) includes `COMMIT`, `ROLLBACK`, and `SAVEPOINT` for managing [[ACID|ACID-compliant]] database transactions. While SQL is a standard, each major RDBMS vendor implements proprietary extensions and deviations, meaning that SQL code is rarely fully portable between systems without modification. The emergence of [[NoSQL|NoSQL]] databases introduced alternative query interfaces, though many NoSQL systems have subsequently adopted SQL-compatible query layers, and [[NewSQL]] databases combine SQL interfaces with distributed architectures designed for horizontal scalability.