Question

I have a DATETIME field in mySQL (fromStamp) with a valid date/time stamp in it.
I need to be able to round the minutes UP to the next 6 minute interval. Seconds should be ignored or treated as :00

So, if my DATETIME is 2013-01-31 13:07:17 I need the result to be 2013-01-31 13:12:00
EXCEPT for times between :00 and :06 and :31 and :36 those need to be rounded DOWN.

 :00-06 round DOWN to 00
 :07-12 round UP to 12
 :13-18 round UP to 18
 :19-24 round UP to 24
 :24-30 round UP to 30
 :31-36 round DOWN to 30
 :37-42 round UP to 42
 :43-48 round UP to 48
 :49-54 round UP to 54
 :55-00 round UP to 00

I found a reasonable way to selectively round down using:

SELECT
  fromStamp, 
  CONCAT(DATE_FORMAT(`fromStamp`, '%Y-%m-%d'), ' ',
         SEC_TO_TIME((TIME_TO_SEC(`fromStamp`) DIV 360) * 360))
FROM `table` 
WHERE (
    DATE_FORMAT(`fromStamp`, '%i') BETWEEN 0 AND 6 
    OR DATE_FORMAT(`fromStamp`, '%i') BETWEEN 31 AND 36
);

Is there a good way of rounding everything else up to the next 6 minute interval?
(I feel like I’m missing something simple)

UPDATE

So I’m going with @mellamokb’s solution but his comment regard seconds is right, it does come into play.

A DATETIME of 2013-01-22 12:24:13 rounds UP to 12:30 which is not what is needed so I’ll first do:

UPDATE table SET fromStamp = CONCAT(DATE_FORMAT(fromStamp, '%Y-%m-%d %h:%i'), ':00'); 

to get rid of the seconds then his query which gets exactly what I’m looking for.

Answer 1

Rounding up is very similar logic, except you add 1 to shift to the next nearest 6-minute interval. I’ve also subtracted 1 from TIME_TO_SEC as a correcting factor, otherwise borderline values such as 06:00 get shifted up the next 6-minute interval, i.e., 12:00.

SEC_TO_TIME( ( (TIME_TO_SEC(`fromStamp`) - 1) DIV 360 + 1) * 360))
                                                      ^^^ add one

To combine the two, use a CASE statement to control which form of rounding is used per record:

SELECT
  fromStamp, 
  CASE WHEN
    DATE_FORMAT(`fromStamp`, '%i') BETWEEN 0 AND 6 
    OR DATE_FORMAT(`fromStamp`, '%i') BETWEEN 31 AND 36
  THEN
    CONCAT(DATE_FORMAT(`fromStamp`, '%Y-%m-%d'), ' ',
         SEC_TO_TIME((TIME_TO_SEC(`fromStamp`) DIV 360) * 360))
  ELSE
    CONCAT(DATE_FORMAT(`fromStamp`, '%Y-%m-%d'), ' ',
         SEC_TO_TIME(((TIME_TO_SEC(`fromStamp`) - 1) DIV 360 + 1) * 360))
  END
FROM `table`

(DEMO)