如何将几个子查询的结果加在一起？

I am running a MySQL query to rank my site's users according to the number of book reviews and recipe reviews they have contributed. After initial issues with a multiple JOIN query, I've switched to a series of subqueries, which is much, much faster. However, although I can extract the numbers of reviews from each member, I can't figure out how to add them together so I can sort by the total number.I am running a MySQL query to rank my site's us