combineQueries function
Folds queries into one SELECT with a json_agg column per query, so
a single supabase db query call returns every result set.
Implementation
String combineQueries(Map<String, String> queries) => [
'select',
[
for (final MapEntry(key: name, value: sql) in queries.entries)
' (select coalesce(json_agg(t), \'[]\'::json) from (\n'
'$sql\n'
' ) t) as "$name"',
].join(',\n'),
].join('\n');