一个解决方案（ SQL Fiddle ）可以是：

  SEC_TO_TIME（（（TIME_TO_SEC（toStampActual）+30）DIV 60）* 60 
 

在 60 （值 30 之前），然后再执行 DIV 。

或者，只需使用 ROUND （ SQL Fiddle ）

  SEC_TO_TIME（（ROUND（TIME_TO_SEC （toStampActual）/ 60））* 60 
 

I have a DATETIME column in a table t with values like:

|toStampActual      |
|-------------------|
|2014-09-09 13:00:00|
|2014-09-09 13:15:03|
|2014-09-09 13:14:55|

I need to be able to update those value to:

|toStampActual      |
|-------------------|
|2014-09-09 13:00:00|
|2014-09-09 13:15:00|
|2014-09-09 13:15:00|

Basically round to nearest minute...anything greater than :30 seconds goes up, anything less goes down.

I've found this answer http://***.com/a/19291128/99401 and changed the SQL to

SELECT TIME_FORMAT(
    SEC_TO_TIME(
        (TIME_TO_SEC(toStampActual) DIV 60) * 60
    ), '%H:%i:%s') AS rounded_time 
FROM `t`

SQL Fiddle

But this only rounds down. How can I round up or down based on the seconds?

One solution (SQL Fiddle) could be:

SEC_TO_TIME(((TIME_TO_SEC(toStampActual)+30) DIV 60) * 60

Which just adds half of the 60 (value of 30) before doing the DIV.

Or, just use ROUND (SQL Fiddle)

SEC_TO_TIME((ROUND(TIME_TO_SEC(toStampActual)/60)) * 60