I use multiple workbooks and each work book contains many worksheets with names of customers which contains their order. I would like to know if it is possible to create formula to calculate a product if any customer should order it.

For instance, in the workbook "April", if customer A order item ASB099 and so does customer B, G, H, K, L (all different worksheet in the workbook). Can someone help me write a formula to add up the quantity of ASB099 within the entire workbook.

To provide more details of each worksheet (customer order). Every worksheet follows the same format in that column B in the worksheet contains the product ID, column I: quantity, column J: weight of the product.

Just from what I can come up in my head, I would like to do something like this: If ASB099 exists on the A column on any worksheet, sum up all of it's corresponding weight in the J column.

I hope someone can help. Thanks for your time.
nichiaichi