SQL QUERY在使用COUNT时显示NULL值

I need to produce the number of healthclub members that are enrolled through their employer(several different employers not just 1) for a monthly membership and what level of membership they have plus their family members. The problem I am having is that currently we do not have any LEVEL D membership but may in the future. I need the report to display ‘0’ when there is no membership. I tried I need to produce the number of healthclub memb