-- 退货业务统一单号；只修改已验证关联的单号快照，保留订单ID、库存、清点、换标及履约状态。
USE baiyue_lastleg;
UPDATE ll_order o
JOIN ll_return_order r ON r.lastleg_order_id=o.id AND r.customer_id=o.customer_id
SET o.order_no=r.return_no, r.lastleg_order_no=r.return_no
WHERE o.order_type='RETURN_RELABEL' AND o.source_order_no=r.return_no
  AND (NOT (o.order_no <=> r.return_no) OR NOT (r.lastleg_order_no <=> r.return_no));

-- 应返回零行；非零表示来源关系异常，须核实，脚本不猜测或改绑。
SELECT r.return_no, o.order_no, r.lastleg_order_no
FROM ll_return_order r JOIN ll_order o ON o.id=r.lastleg_order_id AND o.customer_id=r.customer_id
WHERE o.order_type='RETURN_RELABEL'
  AND (NOT (o.order_no <=> r.return_no) OR NOT (r.lastleg_order_no <=> r.return_no));