How to create internal fields dynamically

Hi,

I am getting the data from MARA table to an internal table. Now I have to show the data according to month wise, like if same material is created in may and just, i have to show that material in may and june like below.

material | may | june |

*************************

m1 | 10 | 5 |

m2 | 20 | 15 |

I have to show this report in ALV.

so how can i get the month columns dynamically for each month?

i.e., when month is changed it has to create a new month.

Plz suggest me.

Regards,

Dhanunjay