感谢大家的帮助，问题已经圆满解决！
以下是引用吹水佬在2018-2-26 16:39:42的发言：
REPLACE max WITH MAX(pw1,pw2,pw3,pw4,pw5,pw6,pw7),;
min WITH MIN(pw1,pw2,pw3,pw4,pw5,pw6,pw7),;
zf WITH (pw1+pw2+pw3+pw4+pw5+pw6+pw7-max-min)/5 ALL
REPLACE max WITH MAX(pw1,pw2,pw3,pw4,pw5,pw6,pw7),;
min WITH MIN(pw1,pw2,pw3,pw4,pw5,pw6,pw7),;
zf WITH (pw1+pw2+pw3+pw4+pw5+pw6+pw7-max-min)/5 ALL
简洁
