php - 如何处理大型 mysql 查询

Question

我有以下问题:

SELECT  p2c.pid AS productNumber,
        p.name AS productName
    ,   (
            SELECT COUNT(*)
            FROM   products2customers
            WHERE  pid = p2c.pid
        ) AS registered
    ,   (
            SELECT COUNT(*)
            FROM   products2customers
            WHERE  pid = p2c.pid
               AND date_add(from_unixtime(purchased), INTERVAL 5 YEAR) >= CURDATE()
        ) AS inWarranty
    ,   (
            SELECT COUNT(*)
            FROM   products2customers
            WHERE  pid = p2c.pid
               AND date_add(from_unixtime(purchased), INTERVAL 5 YEAR) < CURDATE()
        ) AS outOfWarranty
    ,   (
            SELECT DATE_FORMAT( MAX( from_unixtime(purchased) ), '%d.%m.%Y')
            FROM   products2customers
            WHERE  pid = p2c.pid
        ) AS lastPurchased
    ,   (
            SELECT DATE_FORMAT( date_add( MAX( from_unixtime(purchased) ), INTERVAL 5 YEAR), '%d.%m.%Y')
            FROM   products2customers
            WHERE  pid = p2c.pid
        ) AS warrantyUntil
FROM    (
            SELECT DISTINCT
                p2c.pid
            FROM
                products2customers p2c
        ) AS p2c
JOIN
    products p
ON
    p.id = p2c.pid
ORDER BY
    inWarranty DESC

查询是在一个有 25000 行的数据库表上执行的。此查询的执行时间约为 40 秒。结果将显示在网页上，因此等待 40 秒的结果不是很好。

有没有办法执行这个查询并保存它的输出？因为如果每晚执行此查询就足够了。

执行此操作的最佳方法是什么？我应该创建一个 cronjob 并执行此查询并将结果写入数据库吗？或者有更好的方法吗？

或者我可以优化这个查询，让它更快吗？

Answer 1

我认为所有那些相关的子查询都在折磨你。试试这个:

SELECT  p2c.pid AS productNumber,
        p.name AS productName,
        COUNT(*) AS registered,
        SUM(date_add(from_unixtime(purchased), INTERVAL 5 YEAR) >= CURDATE()) AS inWarranty,
        SUM(date_add(from_unixtime(purchased), INTERVAL 5 YEAR) < CURDATE()) AS outOfWarranty,
        DATE_FORMAT( MAX( from_unixtime(purchased) ), '%d.%m.%Y') AS lastPurchased,
        DATE_FORMAT( date_add( MAX( from_unixtime(purchased) ), INTERVAL 5 YEAR), '%d.%m.%Y') AS warrantyUntil
FROM products2customers p2c
JOIN products p ON p.id = p2c.pid
GROUP BY p2c.pid
ORDER BY inWarranty DESC