mysql - 使我的 mysql 查询更加高效

Question

我想要做的是从 Enswitch_Mobile_Users 表中提取 id、phone_type、os_version 列。

通过 id，我只需从 Enswitch_Users 表中获取 enswitch_id。

然后，计算 Enswitch_Android_Purchases 或 Enswitch_Iphone_Purchases 中用户列与 enswitch_mobile_users 中的 ID 匹配的所有整体。并获取第一次输入日期和最后一次输入日期。

我设法让它与这个查询一起工作:

SELECT p.user  AS `Mobile_User_ID`, 
    e.os_version `Os_Version`, 
    e.phone_type `Phone_Type`, 
    eu.enswitch_id `Enswitch_ID`,
    Count(1) AS `Buy_Count`,
    (SELECT pc.date 
        FROM 
        (
            SELECT date, user, status 
            FROM enswitch_android_purchases 
            UNION 
            SELECT date, user, status 
            FROM enswitch_iphone_purchases
        ) AS pc 
        WHERE pc.status = 1 
            AND pc.user = p.user 
        ORDER BY pc.date ASC 
        LIMIT 1) AS `First_Purchase`,
    (SELECT pc.date 
        FROM 
        (
            SELECT date, user, status 
            FROM enswitch_android_purchases 
            UNION 
            SELECT date, user, status 
            FROM enswitch_iphone_purchases
        ) AS pc 
        WHERE pc.status = 1 
            AND pc.user = p.user 
        ORDER BY pc.date DESC LIMIT 1) AS `Last_Purchase`
FROM 
(
    SELECT item, date, user, status 
    FROM enswitch_android_purchases 
    UNION
    SELECT item, date, user, status 
    FROM enswitch_iphone_purchases
) AS p 
LEFT JOIN enswitch_mobile_users e 
    ON p.user = e.id
LEFT JOIN enswitch_users eu 
    ON e.user_id = eu.id
WHERE p.`date` >= :from_date 
    AND p.`date` <= :to_date 
    AND p.user is not null 
    AND p.status = 1
GROUP BY `Mobile_User_ID`

但是由于选择的原因，它会非常慢，所以我怎样才能使它更有效率？

Answer 1

您也许可以使用以下命令，将 SELECT 列表中的两个选择替换为 min(p.date) 和 max(p.date) ):

SELECT p.user  AS `Mobile_User_ID`, 
    e.os_version `Os_Version`, 
    e.phone_type `Phone_Type`, 
    eu.enswitch_id `Enswitch_ID`,
    Count(1) AS `Buy_Count`,
    min(p.date) AS `First_Purchase`,
    max(p.date) AS `Last_Purchase`
FROM 
(
    SELECT item, date, user, status 
    FROM enswitch_android_purchases 
    UNION
    SELECT item, date, user, status 
    FROM enswitch_iphone_purchases
) AS p 
LEFT JOIN enswitch_mobile_users e 
    ON p.user = e.id
LEFT JOIN enswitch_users eu 
    ON e.user_id = eu.id
WHERE p.`date` >= :from_date 
    AND p.`date` <= :to_date 
    AND p.user is not null 
    AND p.status = 1
GROUP BY p.user