This could be done, Melvin.  I did something similar quite some time ago.  1st acquire the current QOH, then you would have to post all sales, purchases, and inv adj, grouped by month, to that amount for as far back as you want to go.  

Hi Dave and Darlene,

I tried it this way. It works for some products but not for others. I'm wondering which part I did wrong. Do you use the TransRow Table to do it? I added stocking_quantity where journal values are 7 and 8, which is inventory adjustment, added Journal 4 which is purchase, and subtract journal 3 which is sales. How do you deal with Journal 9 which is back order I believe. I also use the ROW Type  = 0 as a filter. What other filters do you use? 

Do you mind sharing your SQL script with me?

Thanks,

Melvin

Back Orders should not be a factor, Melvin.  Inventory is not affected by purchase orders or sales orders, only sales, purchases, and adjustments.  I do not still have the code, it was a long time ago.