Why search by date field requires engine to touch all records? Is there any way to avoid it? Following query EXPLAIN select * FROM playdays where realdate>=Date('2010,01,01') ; shows that ...
Just like this example, I cannot even tell the join ordering from it. And what does "ALL" and "ref" in the table mean? Is there any manual about the visual explain?
So I have a medium sized query that hits 15 tables. The query takes 36 sec on MySQL to complete. I ran EXPLAIN on the query and one of the tables returned this. '1', 'SIMPLE', 'mount_adapters', ...