Is it possible to create an index from columns of 2 different tables?
If not, how do we optimize a query that does a
group by on columns of 2 different tables?
For example: the following statement
explain select p.name from Person p join JobStatus js group by p.name,js.job_tickets order by p.name,p.lastname, pm.job_tickets;
Uses indexes if I have for (p.name,p.lastname) and for
But I have noticed that on other queries and with more than one joining table the index is omitted.