scala> df.filter(to_date(df("someTimeStamp")) === "2020-01-01").show
+-------+-------------------+
|someCol|      someTimeStamp|
+-------+-------------------+
|      1|2020-01-01 23:00:01|
|      2|2020-01-01 00:00:00|
|      3|2020-01-01 12:54:00|
+-------+-------------------+