How To Join Two Tables Based On A Timestamp (with Variance Of A Few Seconds)?

I have two tables that I'm trying to join and insert into another table based on a combination of three columns. I'll explain. Table M | ANO | BNO | Timestamp |

Solution 1:

A simple way to speed up the query is by creating a function-based index:

CREATE INDEX indexname1 ON N (timestamp+5/86400);
CREATE INDEX indexname2 ON N (timestamp+6/86400);