Gender
-------
Female
Male
Male
Male
Female
Female
Male
Female
在这里,我想计算性别列的概率和我尝试的以下查询,但它不起作用。
SELECT (count(*)/(SELECT count(*) from DIABETIC_TOPIC) as probability from DIABETIC_TOPIC group by gender order by gender;
我错过了什么?
我将在非分组查询上交叉加入分组查询,并将它们分开:
SELECT gender, cnt_gender / cnt * 100 AS probability
FROM (SELECT gender, COUNT(*)
FROM diabetic_topic
GROUP BY gender) a
CROSS JOIN (SELECT COUNT(*) AS cnt
FROM diabetic_topic) b