SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function concat (children 1)
     ExpressionList (children 2)
      Function toLowCardinality (alias val) (children 1)
       ExpressionList (children 1)
        Literal \'a\'
      Literal \'b\'
   ExpressionList (children 1)
    Identifier val
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier val
