[localhost:21000] default> select 'foo', (select 'bar');
Query: select 'foo', (select 'bar')
Query submitted at: 2019-09-18 13:44:43 (Coordinator: http://tarmstrong-box:25000)
ERROR: AnalysisException: Subqueries are not supported in the select list.
I think we can support these, implemented as a nested loop join with a cardinality check node if needed.
Subqueries in select can result in rows not being returned