SELECT SUM(a.pf_value) totalRating ,COUNT(zy_id) countRating from mic_td_user_pf a

WHERE a.zy_id=199 AND a.pf_type=2spa

显示结果为 co

totalRating countRating

26      7

SELECT b.countRating ,b.totalRating/b.countRating avgRating FROM (SELECT SUM(a.pf_value) totalRating ,COUNT(zy_id) countRating from mic_td_user_pf a

WHERE a.zy_id=199 AND a.pf_type=2) b

countRating avgRating

7          3.71428571428571

保留4位小数

SELECT b.countRating ,round(b.totalRating/b.countRating,4) avgRating

FROM (SELECT SUM(a.pf_value) totalRating ,COUNT(zy_id) countRating

from mic_td_user_pf a  WHERE a.zy_id=199 AND a.pf_type=2 AND a.del_mark = 0) b ;

countRating avgRating

7          3.7143