Related
E071-01, “UNION DISTINCT table operator”
E071-02, “UNION ALL table operator”
F301, “CORRESPONDING in query expressions”
F302, “INTERSECT table operator”
T551, “Optional key words for default syntax”
Normative References
E071-03, “EXCEPT DISTINCT table operator”, is a mandatory feature of ISO/IEC 9075-2. It was present in SQL:1999, which was the first revision of the SQL standard that enumerated the individual features. In SQL-92 except—without the optional keyword distinct—was part of the intermediate level.
