Compare Tables ITEM_A/I_ID with ITEM/I_ID, filtering so that you are only addressing item IDs that start with 25*. Make a list of ITEM lines that ARE NOT in ITEM_A

From that list, create new rows in ITEM_A inserting the following fields
ITEM ITEM_A
a. I_ID I_ID
b. ITEM_R_ID ITEM_R_ID
c. ITEM_DESC SALES_DESC