# `Ash.Query.Function.StartOfDay`
[🔗](https://github.com/ash-project/ash/blob/v3.27.8/lib/ash/query/function/start_of_day.ex#L5)

Converts a date or datetime into the start of day

Accepts an optional time zone, in the same format that can be passed to
`DateTime.new/3`.

For example:
   start_of_day(now()) < a_datetime()
   start_of_day(now(), "Europe/Copenhagen") < a_datetime()

# `args`

# `has_partial_evaluate?`

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*Consult [api-reference.md](api-reference.md) for complete listing*