选择基于countries.havestate的机构ID计数。如果havestate=1，则count（institutions.instituteid）基于stateid，如if（institution.stateid='1'），然后count count（institutions.instituteid），否则count instituteid不带stateid，如下图所示。

SELECT countries.countryid, 
       Count(institutions.instituteid) AS instituteCount 
FROM   countries 
       RIGHT JOIN institutions 
               ON countries.countryid = institutions.countryid 
WHERE  countries.countryid = '32' 
       AND countries.status = '1'