ISO/IEC 9075
ISO/IEC 9075 "Information technology - Database languages - SQL" is an international standard for Structured Query Language, and is considered as specifying the minimum for what a database engine should fulfill in terms of SQL syntax, which is called Core SQL. The standard also defines a number of optional features. History 
The first edition was based on ANSI SQL. Editions 
New editions of the ISO standard are published regularly. Chronological overview of the editions (which have the year of publication in their name):

 SQL-86, ANSI X3.135:1986
 SQL-87, ISO 9075:1987, based on the ANSI standard
 SQL-89, ISO/IEC 9075:1989
 SQL-92, ISO/IEC 9075:1992
 SQL:1999, ISO/IEC 9075:1999
 SQL:2003, ISO/IEC 9075:2003
 SQL:2006, ISO/IEC 9075:2006
 SQL:2008, ISO/IEC 9075:2008
 SQL:2011, ISO/IEC 9075:2011
 SQL:2016, ISO/IEC 9075:2016
 SQL:2019, ISO/IEC 9075:2019
 SQL:2023, ISO/IEC 9075:2023

References

External links
 ISO/IEC JTC 1/SC 32 technical committee (data management and interchange)

SQL
09075