Hi,
I'm a french software engineer. I worked for 10 years as a software engineer, as well as MySQL and SQL Server databases.
For your project, I looked at the stackoverflow link, and I see that you don't use "JOIN". I think it's a pity. And for your query, I can help you for 10$ as you wish.
I am available from now, and for the time you want.
If you have any questions do not hesitate to contact me.
Best Regards.