>>>>the following code in a SQL interrogation always return "0-12"
>>>>
>>>>

>>>>IIF( (HOUR( TTOD( Table1.datecreation)) >=0  AND HOUR( TTOD( Table1.datecreation)) <= 11), "0-12", IIF( (HOUR( TTOD( Table1.datecreation)) >= 12 AND HOUR( TTOD( Table1.datecreation)) <= 15), "12-16", "16-24")) as HourBlock
>>>>

>>>>
>>>>Data contains hours in all the range 0-24. So I should have some "12-16" and "16-24"
>>>>
>>>>You guys see something that I don't?
>>>
>>>What's Set('hour')? Hint: it should be 24 in your case.
>>
>>I thought about it but the help says that "set hours" doesn't make a difference.
>
>I don't see that in help, may I ask where you see it? Anyway, I would try Set Hour = 24 and see what happens to your query.

from my help file

HOUR( ) returns a numeric value based on a 24 hour format, and is not affected by the current setting of SET HOURS. For example, if SET HOURS is 12 or 24, the following command returns 13:

? HOUR({^1998-02-16 1:00p})


And I just tried with set hours 24 and I got the same results.