根据mysql中的条件显示计数值

Question

根据countries.haveState选择instituteId的计数。如果haveState = 1那么，Count（institutionss.instituteid）基于stateId，如if（institution.stateId =＆＃39; 1＆＃39;）然后计数Count（institutions.instituteid），否则计算没有stateId的instituteId，如下所示。

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'