How to use Group in Sqlite database w.r.t. DateColoumn?

I have below coloumn in my SQLite table : DataType of ActivityDate is date provided by Sqlite.

ActivityDate
2016-01-28 07:38:41 +0000
2016-01-28 03:26:56 +0000
2016-01-29 02:22:40 +0000
2016-01-26 01:13:39 +0000

I wants to get uniqe date(Only w.r.t. Date), I do not wants to consider Time in this. So my desired result is :

ActivityDate
2016-01-28 07:38:41 +0000
2016-01-29 02:22:40 +0000
2016-01-26 01:13:39 +0000

So, Is there any way to acheive this using SQLite Query?