J Lumby <johnlumby@hotmail.com> <DM5PR06MB3082AEC288F546F7AF5393E3A3E69@DM5PR06MB3082.namprd06.prod.outlook.com>
writes:
> I am unclear about the rules which postgresql uses in building a result
> set when the select list ( see note ) contains several different
> Set-Returning functions, possibly with sets of different sizes.
The docs you want exist, but they're a bit buried ... see
https://www.postgresql.org/docs/current/xfunc-sql.html#XFUNC-SQL-FUNCTIONS-RETURNING-SET
In particular, the NOTE at the bottom of that section explains that
the behavior changed in v10.
regards, tom lane