提高mysql查询效率

我试图做的是从Enswitch\u Mobile\u Users表中提取id、phone\u type、os\u version列

有了这个id，我只需要从enswitch_用户表中获取enswitch_id

然后，统计所有来自Enswitch_Android_购买或Enswitch_Iphone_购买的、用户Colu与Enswitch_mobile_用户id匹配的实体。获取第一次入境日期和最后一次入境日期

我成功地实现了这个查询：

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`

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但是由于选择的原因，速度会非常慢，因此如何提高效率？

您可以使用以下选项，将选择列表中的两个选择替换为minp.date和maxp.date：

---

您能否显示表模式以使其更简单？

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