Question

I try to select those rows from the table in which datatime is withing 1 minute from now. I try to do it in the following way:

SELECT datetime FROM my_table 
WHERE datetime > date_add( curdate( ) , INTERVAL -1 MINUTE )

This is what I get:

2011-09-23 02:39:53
2011-09-23 08:10:07

Something is clearly wrong with that. Does anybody know why?

ADDED

It looks really strange. If I use interval -1 hour I got results which are 4 or 7 hours old (I should not get them) but I do filter results which are older than 14 hours. How is it possible?

Answer 1

From one minute in the past to one minute in the future:

SELECT * FROM my_table
WHERE datetime BETWEEN
    DATE_ADD(NOW(), INTERVAL -1 MINUTE) AND
    DATE_ADD(NOW(), INTERVAL 1 MINUTE)

From now to one minute in the future:

SELECT * FROM my_table
WHERE datetime BETWEEN
    NOW() AND
    DATE_ADD(NOW(), INTERVAL 1 MINUTE)

From one minute in the past to now:

SELECT * FROM my_table
WHERE datetime BETWEEN
    DATE_ADD(NOW(), INTERVAL -1 MINUTE) AND
    NOW()