题解 | #统计所有课程参加培训人次#
统计所有课程参加培训人次
https://www.nowcoder.com/practice/98aad5807cf34a3b960cc8a70ce03f53
SELECT SUM(course1)+SUM(course2)+SUM(course3) AS staff_nums FROM
(
SELECT
info_id,
staff_id,
IF (course LIKE '%1%', 1, 0) AS course1,
IF (course LIKE '%2%', 1, 0) AS course2,
IF (course LIKE '%3%', 1, 0) AS course3
FROM
cultivate_tb
WHERE
course IS NOT NULL
)A
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