select rownum seq_num, lpad(to_char(level), decode(level, 1, 1, level + 1), '.') bom_level, bbm.ASSEMBLY_ITEM_ID, msi.segment1 assembly_item, msi.description assembly_description, bbm.COMMON_ASSEMBLY_ITEM_ID, bic.item_NUM, bbm.COMMON_BILL_SEQUENCE_ID