题解 | #统计每种性别的人数#
统计每种性别的人数
https://www.nowcoder.com/practice/f04189f92f8d4f6fa0f383d413af7cb8
select case when substring_index(profile,',',-1)='male' then 'male' when substring_index(profile,',',-1)='female' then 'female' end as gender, count(device_id) as number from user_submit group by gender;
解题思路:
步骤1:统计每种性别,group by gender
步骤2:gender来自profile的最后一部分,所以用到substring_index()函数
步骤3:利用case when 语句,加标签,如果substring_index(profile,',',-1)='male' then 'male'...