Ah I see I think you mean then
May 29 2020 08:05:28 since 5.44454 = 5:28 right?
Are you retrofitting data or is this for a new table? In MySQL doing
CURRENT_TIMESTAMP() saves the minute and seconds by default so theres no need to do this. I think all databases have some timestamp-esque function that saves the current minute and second.
Otherwise, if you are retrofitting data, sounds like you will need an update function where you do something like
ADD COLUMN myNewDate datetime;
SET myNewData = DATEFORMAT(some logic here)
That dateformat part will change depending on what database you use, and will give you the opporutnity to say I want the year to be the year dictated by this column, the month from this column, and the minute/seconds based on calculations on this column.
But again, if this is a new table, CURRENT_TIMESTAMP should already take care of minutes and seconds for you.