will need to calculate the frequency of the order have 2 same items,

for example the item A001 and A002 both of them are ordered at same time on same order, result will show 2 (order A12345678 and order C45064838 )

Order# | Item# |

A12345678 | A001 |

A12345678 | A002 |

B23456790 | A003 |

B23456790 | A004 |

C45064838 | A001 |

C45064838 | A002 |

C45064838 | A003 |

the result table

# of order have same 2 item | A001 | A002 |

A001 | 2 | |

A002 | 2 |

what's the formula to get 2 ?

thank you thank you

Joyce