【SQL】根据年月，查询月份中每一天的数据量

传入YYYY-MM-01，查询这个月中每一天的数据量，没有数据的天数用0表示

WITH RECURSIVE DateRange AS (
    SELECT :startDate AS Date
    UNION ALL
    SELECT DATE_ADD(Date, INTERVAL 1 DAY) FROM DateRange
    WHERE Date < LAST_DAY(:startDate)
)
SELECT
    dr.Date,
    COALESCE(COUNT(yt.createTime), 0) AS DataCount
FROM
    DateRange dr
LEFT JOIN
    t_student yt ON DATE(yt.createTime) = dr.Date
GROUP BY
    dr.Date
ORDER BY
    dr.Date

• 示例