Power Query Function That Returns Value Based on Which Columns Have Data

Hi,

In the past I came across a function that would return a value from either Column A, B, C, or D depending if which ones contain data. 

For example:

Col A = USA

Col B = CA

Col C = San Diego County

Col D = San Diego

The function would return the value in Col D, but if no value in Col D, it would look in Col C and if it had a value it would return that.  If both columns C & D don't have values, it would look in Col B, etc..

I know I can accomplish this with an IF statement but I remember seeing a function that handles this. Hoping someone knows the function I am referring to.

Thank you!

Kevin