select d.content,count(s.status) from MesmachineStatus s , Mesmachinestatusdetail d where s.status=d.status group by s.status 正确地

SELECT d.content,count(s.status)from Mes_machinestatus s left JOIN
mes_machinestatusdetail d  on s.status=d.status GROUP BY s.status 错误的

hql 不支持 left join on   要改成where 就可以了

来源：http://blog.csdn.net/zxf1242652895/article/details/53212708