MySQL incorrect key file for tmp table when making multiple joins

Question

I don\'t come here for help often but I am pretty frustrated by this and I am hoping someone has encountered it before.

Whenever I try to fetch records from a table

Answer 1

Using the EXPLAIN keyword may help find out how to best optimize this query. Essentially, what you need to do is get the result set as small as possible as quickly as possible. If you have a result set of every row in core_username until the end, when you order it you run the risk of... this.

If you can do the ordering on core_username alone without a problem, you may want to get the min() row as a subquery.