name VARCHAR(20) NOT NULL,

parent INT DEFAULT NULL);

INSERT INTO category

VALUES(1,'ELECTRONICS',NULL),(2,'TELEVISIONS',1),(3,'TUBE',2),

 (4,'LCD',2),(5,'PLASMA',2),(6,'PORTABLE ELECTRONICS',1),

 (7,'MP3 PLAYERS',6),(8,'FLASH',7),

 (9,'CD PLAYERS',6),(10,'2 WAY RADIOS',6);

SELECT * FROM category ORDER BY category_id;

+-------------+----------------------+--------+

 | category_id | name                  | parent |

+-------------+----------------------+--------+

 |          1 | ELECTRONICS           |   NULL |

 |          2 | TELEVISIONS           |      1 |

 |          3 | TUBE                 |      2 |

 |          4 | LCD                  |     2 |

 |          5 | PLASMA               |      2 |

 |          6 | PORTABLE ELECTRONICS |         1 |

 |          7 | MP3 PLAYERS           |      6 |

 |          8 | FLASH                |      7 |

 |          9 | CD PLAYERS            |      6 |

 |         10 | 2 WAY RADIOS           |     6 |

+-------------+----------------------+--------+

10 rows in set (0.00 sec)