Optimize SQL that uses between clause

Question

Consider the following 2 tables:

Table A:
id
event_time

Table B
id
start_time
end_time

Every record in table A is mapped to exactly 1 reco

Answer 1

I can't think of the reason for you to have a table with 130.000 rows with time intervals. Anyways, there must be a good reason for such design, and if so, you have to avoid trying to compute such a join everytime. So here's my suggestion. I would add a reference to B.id in table A (A.B_ID) and use triggers to maintain consistency. Anytime you add a new record (insert trigger) or the even_time column changes (update trigger), you would recompute the reference to B that this time corresponds to. Your select statement would be reduced to a single select * from A.