I have a shapefile with date in a
string field. I create a new field with
date type and use the calculator to make the conversion. But the result only provide the date part, the time part is removed. Even when the preview show the correct conversion.
Here you can see the original string field
time and the result date
time2. And the use of the conversion function
to_datetime() and the preview result at the end
If you go to the layer properties you can change the edit mode to date/time. Then if go to the data and try to edit
time2 you get the current date/time. So is possible save date and time in the same field. But the update tool still doesn't work as expected
As J.R said. Even when you can change QGIS edit to allow Date/Time the save to shapefile will discard the time.