优化以下Oracle语句： SELECT SUBSTR(msn.serial_number, 1, 10) genset_sn, msi2.segment1 Genset_BOM_NUM, msi2.inventory_item_id, msi.segment1 key_component, mut1.serial_number component_sn, msi.description component_desc, wdj.date_completed, (SELECT MAX(aps.vendor_name) FROM ap_suppliers aps, bom_resources bor, mtl_unit_transactions mut, po_headers_all poh, po_lines_all pol, wip_osp_resources_val_v wor WHERE aps.vendor_id = poh.vendor_id AND bor.resource_id = wor.resource_id AND poh.po_header_id = pol.po_header_id AND pol.item_id = bor.purchase_item_id AND wor.wip_entity_id = mut.transaction_source_id AND mut.serial_number = mut1.serial_number AND mut.inventory_item_id = mut1.inventory_item_id AND mut.organization_id = mut1.organization_id AND mut.receipt_issue_type = 2 AND mut.transaction_source_type_id = 5 ) supplier FROM mtl_material_transactions mmt1, mtl_material_transactions mmt2, mtl_parameters mpa, mtl_serial_numbers msn, mtl_system_items msi, mtl_system_items msi2, mtl_transaction_types mtt1, mtl_transaction_types mtt2, mtl_unit_transactions mut1, mtl_unit_transactions mut2, wip_discrete_jobs_v wdj WHERE mmt1.inventory_item_id = mut1.inventory_item_id AND mmt1.organization_id = mut1.organization_id AND WDJ.PRIMARY_ITEM_ID = msi2.INVENTORY_ITEM_ID AND mmt1.transaction_id = mut1.transaction_id AND mmt1.transaction_source_id = wdj.wip_entity_id AND mmt1.transaction_type_id = mtt1.transaction_type_id AND mtt1.transaction_type_name = 'WIP Issue' AND NOT EXISTS (SELECT 'WIP Negative Issue or WIP Return' FROM mtl_material_transactions mmt3, mtl_transaction_types mtt3, mtl_unit_transactions mut3 WHERE mmt3.transaction_id = mut3.transaction_id AND mmt3.transaction_type_id = mtt3.transaction_type_id AND mmt3.transaction_date > mmt1.transaction_date AND mtt3.transaction_type_name IN ('WIP Negative Issue', 'WIP Return') AND mut3.serial_number = mut1.serial_number AND mut3.inventory_item_id = mut1.inventory_item_id) AND mmt2.transaction_id = mut2.transaction_id AND mmt2.transaction_source_id = wdj.wip_entity_id AND mmt2.transaction_type_id = mtt2.transaction_type_id AND mtt2.transaction_type_name = 'WIP Completion' AND mpa.organization_code = 'WHP' AND msn.current_organization_id = mpa.organization_id AND LENGTH(msn.serial_number) >= 10 AND msi.inventory_item_id = mmt1.inventory_item_id AND msi.organization_id = mmt1.organization_id AND (msi.planning_make_buy_code = 2 OR msi.segment1 LIKE 'SO%') AND mut2.serial_number = msn.serial_number AND mut2.inventory_item_id = msn.inventory_item_id AND mut2.organization_id = mpa.organization_id AND msi2.ORGANIZATION_ID = '323'

优化Oracle语句的一种方式是通过合理的索引设计来提高查询性能。根据给定的语句，以下是可能的索引优化建议：

1. 在以下表中创建索引：mtl_material_transactions、mtl_unit_transactions、mtl_system_items、mtl_parameters、mtl_transaction_types、mtl_serial_numbers、wip_discrete_jobs_v 和 bom_resources。
- 在 mtl_material_transactions 表上创建索引：inventory_item_id、organization_id、transaction_id、transaction_source_id 和 transaction_type_id。
- 在 mtl_unit_transactions 表上创建索引：serial_number、inventory_item_id、organization_id 和 transaction_id。
- 在 mtl_system_items 表上创建索引：inventory_item_id、organization_id 和 planning_make_buy_code。
- 在 mtl_parameters 表上创建索引：organization_code 和 organization_id。
- 在 mtl_transaction_types 表上创建索引：transaction_type_id 和 transaction_type_name。
- 在 mtl_serial_numbers 表上创建索引：current_organization_id、serial_number 和 inventory_item_id。
- 在 wip_discrete_jobs_v 表上创建索引：PRIMARY_ITEM_ID 和 wip_entity_id。
- 在 bom_resources 表上创建索引：resource_id 和 purchase_item_id。

2. 优化子查询：
- 确保子查询中的相关列都有适当的索引。
- 检查子查询是否可以使用连接操作（JOIN）来代替。
- 确保子查询的性能得到优化，可以使用合适的索引或重写子查询。

3. 检查 WHERE 子句中的条件顺序，将最具选择性的条件放在前面。

请注意，优化策略可能因实际数据和数据库配置而异，建议在执行任何更改之前先在测试环境中进行测试和验证。另外，确保数据库统计信息是最新的，以便优化器能够做出更好的执行计划决策。