SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 1) ExpressionList (children 1) Function in (children 1) ExpressionList (children 2) Literal \'Hello\' Subquery (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 1) ExpressionList (children 1) Function materialize (children 1) ExpressionList (children 1) Literal \'Hello\'