Question

Lets say that I have a table with a timestamp column full of records and I want to calculate the smallest time difference between two consecutive records using only one query.

Maybe a table like…

CREATE TABLE `temperatures` (
  `temperature` double,
  `time` timestamp DEFAULT CURRENT_TIMESTAMP
);

Answer 1

Assuming that there is a unique constraint on the time stamp (to prevent there being two recordings at the same time):

SELECT MIN(timediff(t1.`time`, t2.`time`)) AS delta_t,
    FROM temperatures t1 JOIN temperatures t2 ON t1.`time` < t2.`time`

This answers the questions rather precisely – and doesn’t convey other useful information (such as which two timestamps or temperatures).