coalesce
Evaluates each expression in turn until the first valid value is obtained. Invalid values are null and #types-image expressions that are unavailable in the style. If all values are invalid, coalesce returns the first value listed.
Evaluates each expression in turn until the first valid value is obtained. Invalid values are null and #types-image expressions that are unavailable in the style. If all values are invalid, coalesce returns the first value listed.