FAILED: SemanticException Line 7:7 Invalid SubQuery expression 'key' in definition of SubQuery sq_1 [
exists 
  (select count(*) 
  from src a 
  where b.value = a.value  and a.key = b.key and a.value > 'val_9'
  )
] used as sq_1 at Line 5:6: An Exists predicate on SubQuery with implicit Aggregation(no Group By clause) cannot be rewritten. (predicate will always return true).