如何编写平均 innerQuery
How to write average innerQuery
从图像中我有相同的课程 ID 和多个视频,因为我想将整体观看百分比显示为它们的平均值我该怎么做我想要这样的东西:
(SELECT SUM(watched_percentage) FROM tbl_student_learning_path where course_id = 298
AND SELECT COUNT(watched_percentage) FROM tbl_student_learning_path where course_id = 298)
as overallScore
SELECT course_id,AVG(watched_percentage) AS Avg
FROM tbl_student_learning_path
WHERE course_id=298
GROUP BY course_id
根据评论,您可以通过这种方式获得加权平均值
SELECT
course_id,
(100 * SUM(watched_total_time) / SUM(video_total_time)) AS WeightedAvg
FROM
tbl_student_learning_path
WHERE
course_id=298
GROUP BY
course_id
从图像中我有相同的课程 ID 和多个视频,因为我想将整体观看百分比显示为它们的平均值我该怎么做我想要这样的东西:
(SELECT SUM(watched_percentage) FROM tbl_student_learning_path where course_id = 298
AND SELECT COUNT(watched_percentage) FROM tbl_student_learning_path where course_id = 298)
as overallScore
SELECT course_id,AVG(watched_percentage) AS Avg
FROM tbl_student_learning_path
WHERE course_id=298
GROUP BY course_id
根据评论,您可以通过这种方式获得加权平均值
SELECT
course_id,
(100 * SUM(watched_total_time) / SUM(video_total_time)) AS WeightedAvg
FROM
tbl_student_learning_path
WHERE
course_id=298
GROUP BY
course_id