Working with dates

niallkellyyou should always have also a date column and going further also a date dimension, but let's say we are dealing now with just one table and you don't created a date dimension for it, than you have 2 options:
1) Add a date column in Power Query / Calculated Column in DAX and use it for the group by. Better also to just keep the time part in the date time column to have less granularity, very important to model size and can have positive impact on performance. 
2) In case you have auto date time settings enabled in your file than you could do just add 2 times that column to your table and in one of them use the hierarchy Power BI created for you and in the other the column itself. Like this:

Option 1 is much much better 🙂

Hi niallkelly ,

Power BI provide a function to create a Date Hierarchy automaticlly. Please enable it.

File -> Options -> Date load ->Time intelligence

Then these date/time will be grouped.

And different connection patterns can lead to no hierarchy, for more details you can refer this blog.

Why there is no date hierarchy - Microsoft Power BI Community

Or you can create this hierarchy or group by yourself.

right click create hirerarchy or new group. By the way, new group can group date/time by days or hours.

Best Regards

Community Support Team _ chenwu zhu

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