SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function toJSONString (children 1)
     ExpressionList (children 1)
      Identifier c
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Function CAST (alias c) (children 1)
            ExpressionList (children 2)
             Function tuple (children 1)
              ExpressionList (children 3)
               Function CAST (children 1)
                ExpressionList (children 2)
                 Identifier number
                 Literal \'String\'
               Literal NULL
               Function tuple (children 1)
                ExpressionList (children 2)
                 Function CAST (children 1)
                  ExpressionList (children 2)
                   Identifier number
                   Literal \'String\'
                 Literal NULL
             Literal \'Tuple(a Nullable(String), b Nullable(Int64), c Tuple(x Nullable(String), y Nullable(Float64)))\'
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             Function numbers (children 1)
              ExpressionList (children 1)
               Literal UInt64_3
   Set
