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