Re: Text pattern JOINs that use indexes

Richard Brooksby <rb@ravenbrook.com> writes:
> explain select * from files where name like 'foo%';

This is indexable because the LIKE pattern is a constant at plan time,
and so the planner can see that there's a useful range constraint
extractable from the pattern.

> explain select * from test join files on files.name like test.filename
> || '%';

This is not indexable, because the LIKE pattern is not constant.

            regards, tom lane