user18610

Solution was (CASE WHEN `2016` IS NULL THEN '0' ELSE `2016` END)+ (CASE WHEN `2017` IS NULL THEN '0' ELSE `2017` END)+ (CASE WHEN `2018` IS NULL THEN '0' ELSE `2018` END) I think NULL has to be capitalised, as I had tried somethign simiilar before without success.

Thanks I will look into this!