Database export sql - Please tell me how to write mysql batch database export statement. Can it be implemented in one sentence?

 订单表trade字段：stock_num 已使用库存数字段：num 商品总数字段：num_iid 商品id

 商品表goods字段：total_stock_num 总库存数字段：num_iid 商品id

Requirements to achieve:
Automatically reduce the number of total_stock_num, then set it to stock_num, and update the value of total_stock_num at the same time

Note:
1. stock_num may already have a value, where to reduce When adding the original value, it is required that stock_num<=num
2. total_stock_num may be 0, may be less than num (then subtract as much as you want), or may be greater than num (this can be subtracted directly)

I don’t have any coins, what should I do? Can anyone help me with the answer? Thank you
Since there are thousands of orders to be shipped out in batches, what I currently think of is to query and process them in the program, but this will require a lot of SQL to be executed

 例子1:stock_num=2 num=5 total_stock_num=100出库后：stock_num=5 num=5 total_stock_num=97

 例子2:stock_num=0 num=5 total_stock_num=100出库后：stock_num=5 num=5 total_stock_num=95

 例子3:stock_num=2 num=5 total_stock_num=2出库后：stock_num=4 num=5 total_stock_num=0