SQL permits application designers to manipulate sets of rows with a non-procedural (or :"declarative") language, rather than writing iterative loops in conventional languages that process records one at a time.
You specify the result you want, not how to derive it with set processing operations like joins and subqueries to achieve the result you want.
In 1981, The SQL database language was first introduced commercially by Oracle.
The scope of SQL is the definition of data structure and the operations on data stored in that structure.
In 1989, the American National Standards Institute (http://www.ansi.org) published a SQL specification. The ANSI SQL standard was revised in 1992 and this is often referred to as:
- or SQL-2.
The latest ISO SQL standard is currently ISO/IEC 9075:1992.
SQL-99 or SQL:1999 is the current standard. SQL-99 is sometimes called SQL-3. The latest standard is SQL:2003 or SQL:200n. This standard is currently under development.
Most major database vendors support the SQL-92 standard. However, the levels of conformance vary. Some vendors have gone beyond the SQL-92 standard and most have their own extensions to the SQL language.