SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function arrayReduce (children 1)
     ExpressionList (children 2)
      Literal \'sumMerge\'
      Function array (children 1)
       ExpressionList (children 1)
        Function sumState (children 1)
         ExpressionList (children 1)
          Identifier y
    Function finalizeAggregation (children 1)
     ExpressionList (children 1)
      Function sumState (children 1)
       ExpressionList (children 1)
        Identifier y
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Function toNullable (alias y) (children 1)
            ExpressionList (children 1)
             Literal UInt64_42
