"Edit queries" vs "Data" tab

[nadian]

Hi,

What is the difference between editing queries using the "Edit queries" tab vs the "Data" tab?

For example I can add a calculated column in both ways, but what would be the difference?

Thanks!

[MattAllington]

Generally you should add columns in edit queries. Calculated columns in the data view are generally less compressed and less efficient. In fact it is better to create the calc column back in the source if you can. If you can't, then edit query is fine. Calc column in data view should be your last choice. 

Also, do you really need a calc column? Read my blog post here if you are interested. http://exceleratorbi.com.au/calculated-columns-vs-measures-dax/

[nadian]

Thanks for the detailed answer.

Your blog is very usefull and interesting and will definetly affect my future work with DAX.