如何优化查询？

I've written a query to pull a report from a WordPress database. The query is unbelievable slow so I want to optimize it. I've done a bit of research and am having trouble understanding what is the best way top speed up the query (which, even though I wrote, I barely understand what I did.) Can someone point me in the right direction toward optimizing this slow query.I've written a query to pull a report from a Wo