DateTime columns can be tricky for analysis purposes. They don’t work well with Pivot Tables because of the time part, each value seems unique to the Pivot Table & it also creates problems while creating relationships with Date Dimensions. And so, It’s a common need to convert them to just Date before analyzing data & also a common need to create a relationship between the Date (and not DateTime) with Date Dimension Table.
So if it’s possible, I try to do the data type conversion in the source system query. If your source system is SQL Server, you could use this piece of code:
select [your-fields],cast([DateTime_Col] as date) as Date_Col from TableName
Doing the data type conversion upfront in the source system query is a good thing to do. And I hope this is helpful.