SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function JSONExtract (children 1)
     ExpressionList (children 3)
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal \'{"string_value":null}\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal \'string_value\'
      Literal \'LowCardinality(Nullable(String))\'