6.1 KB · ⇊ 5 parts · ⤓ Micron 6.1 KB · ⤓ HTML 28.8 KB

top

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 1.5–2. Many of the new features had already been implemented by vendors before the new standard was adopted.cite-ref-meltonsimon1993-1-0[1] 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

• New features

• Extensions

• References

• External links

• ANSI X3.135-1992

• ISO/IEC 9075:1992cite-ref-2[2]

• FIPS PUB 127-2

Significant new features include:cite-ref-3[3]

• New data types defined: DATE, TIME, TIMESTAMP, INTERVAL, BIT string, VARCHAR strings, and NATIONAL CHARACTER strings.

• Support for additional character sets 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 UNION, UNION ALL, CROSS JOIN, and formalized JOIN types (INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN).

• Conditional expressions with CASE. For an example, see Case (SQL).

• Support for alterations of schema definitions via ALTER and DROP.

• Bindings for C, Ada, and MUMPS.

• New features for user privileges.

• New integrity-checking functionality such as within a CHECK constraint.

• A new information schema—read-only views about database metadata like what tables it contains, etc. For example, SELECT * FROM INFORMATION_SCHEMA.TABLES;.

• Dynamic execution of queries (as opposed to prepared).

• Better support for remote database access.

• Temporary tables; CREATE TEMP TABLE etc.

• Transaction isolation levels.

• New operations for changing data types on the fly via CAST (expr AS type).

• Scrolled cursors.

• Compatibility flagging for backwards and forwards compatibility with other SQL standards.

Two significant extensions were published after standard (but before the next major iteration.)

• SQL/CLI (Call Level Interface) in 1995

• SQL/PSM (stored procedures) in 1996

cite-note-meltonsimon1993-11. ↑ citerefjim-meltonalan-r-simon1993Jim Melton; Alan R. Simon (1993). Understanding The New SQL: A Complete Guide. Morgan Kaufmann. pp. 11–12. ISBN 978-1-55860-245-8.

cite-note-22. ↑ "ISO/IEC 9075:1992". Retrieved 4 June 2025.

cite-note-33. ↑ 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

• The SQL-92 standard