Custom Column in M with Query Editor or in Desktop with DAX?

[giro17]

HI guys

In Power BI Desktop, it is possible to create custom columns in the Query Editor using M, but it is also possible to create columns in Desktop using a DAX formula. 

What are the advantages/disadvantages of the techniques? Is one better than the other? and why?

cheers

[Anonymous · Accepted solution]

If given the choice, adding a column via Power Query (M) is the best practise.  It has performance benefits mainly.

There are times that I create DAX calculated columns, but these are only in cases where I want to make use of the table relationships and measures in calculating the result.

Add your columns in Power Query whereever possible.