组织数据库&多核列通过cronjob [英] Organize database & multichoice columns by cronjob

问题描述

seller:
  id, age, origin, gender, buyer_age, buyer_origin, buyer_gender

buyer:
  id, age, origin, seller_age, seller_origin, seller_gender

这里我们建议买家从这个卖家购买

和

建议卖家向买家销售商品

with cronjob。

改用一个查询的foreach卖家。什么是最有效的方式来做呢？我不想选择每一个，并获得信息，然后更改查询，再次SELECT，这是一个杀死进程在编码和使用系统内存。如果有可能使用join或下面的语句，那么就可以了。

如果卖方或买方说年龄和来源对我来说不重要，那怎么可能呢？有

Here we want to suggest the buyer to buy from this seller
AND
suggest the seller to sell things to the buyer
with cronjob.
Doing it with one query is preferred instead of foreach seller. What's the most efficient way to do it? I don't want to SELECT each one and get info then change the query and again SELECT that's a killing process in coding and using system memory. If there's a possibility of using join or so with below statement then it's OK.
If seller or buyer says age and origin is NOT important for me, then how is it possible? Is there

 WHERE seller_origin = ANY

在mysql中？

推荐答案

SELECT *
FROM seller       
INNER JOIN buyer
ON
        (seller.buyer_gender = buyer.gender OR seller.buyer_gender IS NULL) AND
        (buyer.seller_gender = buyer.gender OR buyer.seller_gender IS NULL) AND
        (seller.buyer_origin = buyer.origin OR seller.buyer_origin IS NULL) AND
        (buyer.seller_origin = seller.origin OR buyer.seller_origin IS NULL) AND
        (seller.buyer_age = buyer.age OR seller.buyer_age IS NULL) AND
        (buyer.seller_age = seller.age OR buyer.seller_age IS NULL)  

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