SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function concatWithSeparator (children 1)
     ExpressionList (children 3)
      Literal \'|\'
      Literal \'a\'
      Function concatWithSeparator (children 1)
       ExpressionList (children 2)
        Literal \'|\'
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal \'x\'
          Literal \'LowCardinality(String)\'
   ExpressionList (children 1)
    Literal \'a\'
