题解 | 统计所有课程参加培训人次 逗号数量+1就是这个人培训课程数
统计所有课程参加培训人次
https://www.nowcoder.com/practice/98aad5807cf34a3b960cc8a70ce03f53
select sum(course_count) as staff_nums
from (
select staff_id,
case
when course is null then 0
else (length(course) - length(replace(course, ',', '')) + 1)
end as course_count
from cultivate_tb
) as a;
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