grouping Timestamps

[#1]

I would like to group my timestamps into per 15 min interval.

if(Minute(datetime)<15, Date#(date(datetime, 'yyyy-MM-dd hh:15'), 'yyyy-MM-dd hh:15'),

  (if(Minute(datetime)<30, Date#(date(datetime, 'yyyy-MM-dd hh:30'), 'yyyy-MM-dd hh:30'),

      (if(Minute(datetime)<45, Date#(date(datetime, 'yyyy-MM-dd hh:45'), 'yyyy-MM-dd hh:45'),

           (if(Minute(datetime)>00, Date#(date(datetime, 'yyyy-MM-dd hh:00'), 'yyyy-MM-dd hh:00')

))))) as datetime2

I tried to put into my loadscript.  It does not seem to work.  The final output i see is skipped by hours.

Pls help.

thanks!

[Gysbert_Wassenaar · Accepted solution]

timestamp(ceil(datetime,1/96),'YYYY-MM-DD hh:mm') as datetime2

[#3]

Got it. But any reasons why the formula does not give the result?