MySQL中的组函数能否嵌套使用? 例如: select max(avg(salary)) from employee group by department_id;

SELECT PT.PRES_NAME,PT.YRS_SERV,AVG(EN.VOTES)

FROM PRESIDENT PT,ELECTION EN

WHERE PT.PRES_NAME=EN.CANDIDATE AND PT.STATE_BORN='Texas'

GROUP BY PT.STATE_BORN，PT.PRES_NAME,PT.YRS_SERV

如果不想让他们分组就这样

SELECT AVG(EN.VOTES)

FROM PRESIDENT PT,ELECTION EN

WHERE PT.PRES_NAME=EN.CANDIDATE AND PT.STATE_BORN='Texas'

GROUP BY PT.STATE_BORN

SELECT PT.PRES_NAME,PT.YRS_SERV,AVG(EN.VOTES)

FROM PRESIDENT PT,ELECTION EN

WHERE PT.PRES_NAME=EN.CANDIDATE AND PT.STATE_BORN='Texas'

GROUP BY PT.STATE_BORN，PT.PRES_NAME,PT.YRS_SERV

如果不想让他们分组就这样

SELECT AVG(EN.VOTES)

FROM PRESIDENT PT,ELECTION EN

WHERE PT.PRES_NAME=EN.CANDIDATE AND PT.STATE_BORN='Texas'

GROUP BY PT.STATE_BORN