Export memory and Import memory

Hi all,

Pls help me by posting some good examples of Export memory id and import memory id concept.

Im in Field exit object where i've to export the available quantity in MIGO(erfmg) into one itab- field1(as temp storage) and import the same into a itab field 2 by memory-id concept.

Why i need this,i've to give a conditional range in between the qty.

Ex:

"Export itab from itab to memory id 'MID'."

"import itab to itab from memory id 'MID'."

hope u understand, and pls post me some good examples.

thanks & regards

sankar.