The SECONDS() functions has resolution of 10 milliseconds, DATETIME() only 1 second.

>DATETIME() doesn't have that limitation...
>
>>No, AFAIK, but you can use SECONDS() function to calculate it. This way you can measure duration of any process, not just SQL Select

ltStart = DATETIME()
>>SELECT ....
>>lnTotalSeconds= DATETIME() - ltStart

Just remember that SECONDS() returns number of seconds since midnight. Add 86400 if your process croses midnight. lnTotalTime will be negative number in this case.