SELECT *,
(
SELECT SUM(value)
FROM mytable mi
WHERE mi.tstamp BETWEEN m.tstamp - '5 minute'::INTERVAL AND m.tstamp
) AS maxvalue
FROM mytable m
ORDER BY
maxvalue DESC
LIMIT 1
I PostgreSQL 11 och högre:
SELECT SUM(value) OVER (ORDER BY tstamp RANGE '5 minute' PRECEDING) AS maxvalue,
*
FROM mytable m
ORDER BY
maxvalue DESC
LIMIT 1