Concatenate text based on if condition

Hello, 

I need to concatenate text based on several columns with if condition.

My formula is the following:

(if [column1] <> 0 then "1" else "") & (if [Column2] <> 0 then "2" else "") & (if [Column3] <> 0 then "3" else ""))

My goal is to get "123" if none of my columns have a zero value, but I'd like to get "12" or "13" or "1" if some of my columns contain zero values. Yet, the else "" creates an error, it seems that power BI can't concatenate values if one of the value is "".

Do you have any idea of how to solve this issue ? 

Thanks !