View source for SQL-92

{{Short description|1992 edition of the SQL standard}}
{{infobox technology standard|first_published=November 1992|domain=[[SQL]]}}
{{SQL language revisions}}
'''SQL-92''' (also called SQL 2) was the third revision of the [[SQL]] [[database]] [[query language]]. Unlike SQL-89, it was a major revision of the standard.  Aside from a few minor incompatibilities, the SQL-89 standard is forward-compatible with SQL-92.

The standard specification itself grew about five times compared to SQL-89. Much of it was due to more precise specifications of existing features; the increase due to new features was only by a factor of 1.5&ndash;2. Many of the new features had already been implemented by vendors before the new standard was adopted.<ref name="MeltonSimon1993">{{cite book|author1=Jim Melton|author2=Alan R. Simon|title=Understanding The New SQL: A Complete Guide|year=1993|publisher=Morgan Kaufmann|isbn=978-1-55860-245-8|pages=[https://archive.org/details/understandingnew00melt/page/11 11–12]|url-access=registration|url=https://archive.org/details/understandingnew00melt/page/11}}</ref> However, most of the new features were added to the "intermediate" and "full" tiers of the specification, meaning that conformance with SQL-92 entry level was scarcely any more demanding than conformance with [[SQL-89]].

The next revision is [[SQL:1999]] (SQL3).
==Related official standard==
* ANSI X3.135-1992
* ISO/IEC 9075:1992<ref>{{cite web |url=https://www.iso.org/standard/16663.html |title=ISO/IEC 9075:1992 |access-date=4 June 2025}}</ref>
* FIPS PUB 127-2

==New features==
Significant new features include:<ref>[[C. J. Date]] with [[Hugh Darwen]]: ''A Guide to the SQL standard : a users guide to the standard database language SQL, 4th ed.'', Addison Wesley, USA 1997, {{ISBN|978-0-201-96426-4}}</ref>
* New data types defined: <code>DATE</code>, <code>TIME</code>, <code>TIMESTAMP</code>, <code>INTERVAL</code>, <code>BIT</code> string, <code>VARCHAR</code> strings, and <code>NATIONAL CHARACTER</code> strings.
* Support for additional [[character set]]s beyond the base requirement for representing SQL statements.
* New scalar operations such as string concatenation and [[substring]] extraction, date and time mathematics, and conditional statements.
* New set operations such as <code>UNION</code>, <code>UNION ALL</code>, <code>CROSS JOIN</code>, and formalized <code>JOIN</code> types (<code>INNER JOIN</code>, <code>LEFT JOIN</code>, <code>RIGHT JOIN</code>, <code>FULL OUTER JOIN</code>).
* Conditional expressions with <code>CASE</code>. For an example, see [[Case (SQL)]].
* Support for alterations of [[Data Definition Language|schema definitions]] via <code>ALTER</code> and <code>DROP</code>.
* Bindings for [[C (programming language)|C]], [[Ada (programming language)|Ada]], and [[MUMPS]].
* New features for user privileges.
* New integrity-checking functionality such as within a [[Check Constraint|<code>CHECK</code> constraint]].
* A new ''information schema''&mdash;read-only views about database metadata like what tables it contains, etc. For example, <code>SELECT * FROM INFORMATION_SCHEMA.TABLES;</code>.
* Dynamic execution of queries (as opposed to prepared).
* Better support for remote database access.
* Temporary tables; <code>CREATE TEMP TABLE</code> etc.
* [[Database transaction|Transaction]] [[Isolation (database systems)|isolation levels]].
* New operations for changing data types on the fly via <code>CAST (expr AS type)</code>.
* [[Cursor (databases)#Scrollable cursors|Scrolled cursors]].
* Compatibility flagging for backwards and forwards compatibility with other SQL standards.

== Extensions ==
Two significant extensions were published after standard (but before the next major iteration.)
* [[SQL/CLI]] ([[Call Level Interface]]) in 1995
* [[SQL/PSM]] ([[stored procedure]]s) in 1996

==References==
{{Authority Control}}
{{reflist}}

==External links==
* [http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt The SQL-92 standard]

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[[Category:SQL|*]]
[[Category:Declarative programming languages]]
[[Category:Programming languages created in 1992]]