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且构网 - 分享程序员编程开发的那些事

检查满足特定条件的最大连续天数

更新时间:2023-02-10 09:59:33

只要在users_id和Drinks_id上有一个复合索引,此解决方案的效果似乎就很好-

This solution seems to perform quite well as long as there is a composite index on users_id and beverages_id -

SELECT *
FROM (
    SELECT t.*, IF(@prev + INTERVAL 1 DAY = t.d, @c := @c + 1, @c := 1) AS streak, @prev := t.d
    FROM (
        SELECT DATE(timestamp) AS d, COUNT(*) AS n
        FROM beverages_log
        WHERE users_id = 1
        AND beverages_id = 1
        GROUP BY DATE(timestamp)
        HAVING COUNT(*) >= 5
    ) AS t
    INNER JOIN (SELECT @prev := NULL, @c := 1) AS vars
) AS t
ORDER BY streak DESC LIMIT 1;