Question

I am attempting to find ‘entries’ create today (in my current timezone) using the following:

Entry.where("DATE(created_at) = DATE(?) AND email = ?", Time.now, email)

Time.now is giving me the time in the current zone, but the query seems like it is searching against the UTC time of each entry’s created_at column.

Any ideas how I can find entries created today in the server’s timezone?

Answer 1

You’re losing track of the timezone information as soon as you call the DATE() function in your SQL. There are two things to keep in mind:

1. Everything inside the database will be in UTC and everything includes the result of DATE().
2. A single date (i.e. day) in your local time zone can easily cross two dates in UTC so you need to look at the entire timestamp (on both sides) rather than just the (UTC) date components.

Something like this should work:

now = Time.now
Entry.where('created_at between :start and :end and email = :email',
    :start => now.beginning_of_day,
    :end   => now.end_of_day,
    :email => email
)

The times should be converted to UTC automatically. You might want to handle the upper bound a little differently; using end_of_day gives you 23:59:59 so there is a little room for something to slip through that you want to capture. You can get around that problem using an explicit half-open interval (rather than the closed interval that SQL’s between uses) like this:

now = Time.now
Entry.where('created_at >= :start and created_at < :end and email = :email',
    :start => now.beginning_of_day,
    :end   => now.tomorrow.beginning_of_day,
    :email => email
)