choosing Partition for mysql table
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I have have below table structure.

    CREATE TABLE IF NOT EXISTS `dnddata` (
      `area_code` int(5) NOT NULL,
      `phonenumber` varchar(14) NOT NULL,
      `preference` varchar(15) NOT NULL,
      `opstype` varchar(1) NOT NULL,
      `phonetype` varchar(1) NOT NULL,
      PRIMARY KEY (`numbers`)
    ) ENGINE=MyISAM DEFAULT CHARSET=latin1;

i want to create one partition on `area_code` another on `phonenumber` .

This is the table structure for dnd mobile numbers. data is very huge approximately 60 million records.

unique area_code values are approx 26.

Please suggest me which partition need to create.

Thanks..