The following did not work because subqueries were limited to select_core grammar:
$ sqlgg -
select * from (select 1 union select 2);
==> select * from (select 1 union select 2)
Position 1:29 Tokens: union select 2)
Error: Sqlgg.Sql_parser.MenhirBasics.Error
Errors encountered, no code generated
The following worked:
The following did not work because subqueries were limited to select_core grammar: