通过组合表增加连接查询响应时间

We have a sports shopping website that recommends products to users. our query recommends by doing a JOIN on three tables of the following effect: (1) what sports a user is interested in, (2) what products are part of that sport, and (3) eliminate products the user has already bought. We have three tables currently. The response time is 3 seconds. We have a sports shopping website that recommen