-- 添加过磅日期字段
ALTER TABLE stock_in_record
    ADD COLUMN weighing_date timestamp COMMENT '过磅日期';

-- 添加过磅日期字段
ALTER TABLE stock_out_record
    ADD COLUMN weighing_date timestamp COMMENT '过磅日期';

-- 添加净重字段
ALTER TABLE stock_inventory
    ADD COLUMN net_weight DECIMAL(16,3) COMMENT '净重';