DateTime.truncate(datetime, :second) not working?

Questions / Help
1

This is driving me nut.

I’m simply trying to write the following query:

    Meeting
    |> where([m], m.updated_at < ^DateTime.truncate(update_started_at, :second))

but I still get:

** (ArgumentError) :utc_datetime expects microseconds to be empty, got: #DateTime<2021-02-22 16:50:09.472646Z>

Use `DateTime.truncate(utc_datetime, :second)` (available in Elixir v1.6+) to remove microseconds.

I also tried to apply the truncate function to to m.updated_at part of it but I also get an error.

I’m guessing I could make it work using utc_datetime_usec but I don’t want to write a migration for such basic query.

There must be a way.

Btw: the documentation is pretty unclear on whether the truncate part should apply to the query side or to the interpolated side of the macro.

Thanks for the help

2

This sounds like you have stored items in the db with microsecond precision and then moved to a newer version of ecto, which now no longer expects those microseconds for a field of type :utc_datetime.

Which one of the two matches: …, got: #DateTime<2021-02-22 16:50:09.472646Z>?

3

Thanks @LostKobrakai for your help.

This sounds like you have stored items in the db with microsecond precision and then moved to a newer version of ecto

It could have been that but this module is actually quite new so I don’t think this is the case.

Which one of the two matches: …, got: #DateTime<2021-02-22 16:50:09.472646Z>?

It seems like it is the update_started_at datetime, which makes it even less coherent. :frowning:

4

Can you move the DateTime.truncate outside the query? Because then ecto shouldn’t even know about the non truncated date.

5

Ok my bad, the issue happened later at:

    meeting
    |> change(%{deleted_at: DateTime.utc_now()})

which works with:

    meeting
    |> change(%{deleted_at: DateTime.truncate(DateTime.utc_now(), :second)})

Sorry for the mistake and thanks for the help!