EF Core 6 和 SQLite 中的 TimeOfDay 问题

Question

I have a problem querying a SQLite database using EF Core 6.

The query is pretty simple:

_context.SomeTable
        .AsNoTracking()
        .Where(x => x.SomeDateTimeColumn.Value.TimeOfDay <= DateTime.Now.TimeOfDay)
        .ToList();

The exception message states that the query could not be translated:

The LINQ expression 'DbSet().Where(t => t.SomeDateTimeColumn.Value.TimeOfDay <= DateTime.Now.TimeOfDay)' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation...

My problem is that, according to the documentation, DateTime.TimeOfDay should be supported by the SQLite database provider. See here: https://docs.microsoft.com/en-us/ef/core/providers/sqlite/functions#date-and-time-functions

Does anyone know the reason for this or could point me to what I'm missing?

Answer 1

TimeSpan values are not yet supported by EF Core. Please upvote issue #18844 .

Hmm, you might be able to do it using Ticks . But the precision might be kinda bad.

x.SomeDateTimeColumn.Value.Ticks % 864000000000 <= DateTime.Now.Ticks % 864000000000

For better precision, you can manually map the julianday function.

Answer 2

I think it might be related to the way DateTime works.

Instead of using:

_context.SomeTable
    .AsNoTracking()
    .Where(x => x.SomeDateTimeColumn.Value.TimeOfDay <= DateTime.Now.TimeOfDay)
    .ToList();

Try this:

_context.SomeTable
    .AsNoTracking()
    .Where(x => x.SomeDateTimeColumn <= DateTime.Now)
    .ToList();