| First published | November 1992 |
|---|---|
| Domain | SQL |
SQL-92 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.[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.
Later revisions of the standard include SQL:1999 (SQL3), SQL:2003, SQL:2008, SQL:2011, SQL:2016 and SQL:2023.
Significant new features include:[2]
DATE, TIME, TIMESTAMP, INTERVAL, BIT string, VARCHAR strings, and NATIONAL CHARACTER strings.UNION JOIN, NATURAL JOIN, set differences, and set intersections.CASE. For an example, see Case (SQL).ALTER and DROP.CHECK constraint.SELECT * FROM INFORMATION_SCHEMA.TABLES;.CREATE TEMP TABLE etc.CAST (expr AS type).Two significant extensions were published after standard (but before the next major iteration.)
