题解 | #统计每种性别的人数#
统计每种性别的人数
http://www.nowcoder.com/practice/f04189f92f8d4f6fa0f383d413af7cb8
SELECT (CASE WHEN CHAR_LENGTH(profile)=18 THEN 'male'
ELSE 'female' END) AS gender,COUNT(*) number
FROM user_submit
GROUP BY gender;#这个方法不是很保险,前提前面字符个数都相等