Informix SQL Compare DateTime value on Where Statement

Question

I have a datetime field called entrytimestamp, with content of the field is for example: 2014-01-07 16:20:00. I would like to query all the data that has entrytimestamp after 09:00:00 o'clock, regardless what date it was.

I have a prototype query:

select *
from trading
where to_char(entrytimestamp, "%H%M%S") >= "090000"

But I think it is logically a mistake, because it will compare the text string, not the sequence value. What is the right way to do it?

Answer 1

Use the EXTEND() function to extract the time part:

select *
from mytable
where extend(entrytimestamp, hour to second) > '09:00:00'