[gavinray]

MULTISET is the SQL native way of doing this but it's only implemented in Oracle, and most people have never heard of it

jOOQ emulates this feature for arbitrary databases and has the best explanatory article on the web about MULTISET imo

https://www.jooq.org/doc/latest/manual/sql-building/column-e...

[lukaseder]

Informix also supports MULTISET natively. Many others support ARRAY, which is equivalent for all practical purposes. jOOQ popularised MULTISET over ARRAY because the existing ARRAY support was less user friendly, mapping results to actual Java array types.