In Postgres is it possible to retrieve distinct date data if the table only contains the datetime field?

The data is stored as follows

2011-04-29 11:35:24.567

I would like a query SELECT DISTINCT ...

That will return data along the lines of

2011-04-2开发者_Python百科8
2011-04-29
2011-04-30

You just need to cast it as date:

SELECT DISTINCT
    col_name::date
FROM
    table_name