Php 需要帮助以较少的联接优化MySQL查询吗

您好，我有下面的sql查询，它可以工作，但有点慢

SELECT 
    ep . *,
    t_u.sUsername AS sLockedBy,
    epi.sName,
    em.sName AS sManufacturerName,
    SUM(IF(eop.dInProduction IS NULL
            AND eop.dFromProduction IS NULL
            AND eop.dShipped IS NULL
            AND eop.nIsCancelled = 0
            AND eos.sStatusCode NOT IN ('Canceled' , 'Finished', 'Complete'),
        1,
        0)) AS nProductOrdered,
    SUM(IF(eop.dInProduction IS NOT NULL
            AND eop.dFromProduction IS NULL
            AND eop.dShipped IS NULL
            AND eop.nIsCancelled = 0
            AND eos.sStatusCode NOT IN ('Canceled' , 'Finished', 'Complete'),
        1,
        0)) AS nProductInProduction,
    SUM(IF(eop.dInProduction IS NOT NULL
            AND eop.dFromProduction IS NOT NULL
            AND eop.dShipped IS NULL
            AND eop.nIsCancelled = 0
            AND eos.sStatusCode NOT IN ('Canceled' , 'Finished', 'Complete'),
        1,
        0)) AS nProductFromProduction,
    SUM(IF(eop.dInProduction IS NULL
            AND eop.dFromProduction IS NULL
            AND eop.dShipped IS NULL
            AND eop.nIsCancelled = 0
            AND eos.sStatusCode NOT IN ('Canceled' , 'Finished', 'Complete'),
        1,
        0)) + ep.nInStock AS nStockCheck
FROM
    eshop3_products AS ep
        LEFT JOIN
    users AS t_u ON ep.nUserLockID = t_u.nUID
        AND t_u.nDeleted = 0
        INNER JOIN
    eshop3_products_i18n AS epi ON ep.nUID = epi.nProductID
        AND epi.nLangID = 1
        AND epi.nDeleted = 0
        LEFT JOIN
    eshop3_manufacturers AS em ON ep.nManufacturerID = em.nUID
        AND em.nDeleted = 0
        LEFT JOIN
    eshop3_order_products AS eop ON ep.nUID = eop.nProductID
        LEFT JOIN
    eshop3_orders AS eo ON eop.nOrderID = eo.nUID
        LEFT JOIN
    eshop3_order_statuses AS eos ON eo.nUID = eos.nOrderID
        AND eos.nUID = (SELECT 
            nUID
        FROM
            eshop3_order_statuses as eos
        WHERE
            eo.nUID = eos.nOrderID
        ORDER BY eos.nUID DESC
        LIMIT 1)
WHERE
    (ep.nDeleted = 0)
GROUP BY ep.nUID
ORDER BY ep.sStoreCode ASC

产品表共有462行

订单状态表共有17154行

查询的执行时间是1.5秒，我认为这很慢

我在ON子句中使用内部SELECT来获取给定订单的最后状态，这里我认为有问题

当我从整个查询中删除订单状态表时，执行时间比0.152秒快几倍

你能给我一些建议我如何优化我的查询

这是sql和explain

id  select_type        table type   possible_keys    key      key_len ref                            rows  Extra
1   PRIMARY            epi   ALL    nProductID                                                        408  Using where; Using temporary; Using filesort
1   PRIMARY            ep    eq_ref PRIMARY,nUID     PRIMARY        4 dragoni_zfms.epi.nProductID       1  Using where
1   PRIMARY            em    eq_ref PRIMARY          PRIMARY        4 dragoni_zfms.ep.nManufacturerID   1 
1   PRIMARY            t_u   eq_ref PRIMARY          PRIMARY        4 dragoni_zfms.ep.nUserLockID       1 
1   PRIMARY            eop   ref    id_productid     id_productid   5 dragoni_zfms.ep.nUID             13 
1   PRIMARY            eo    eq_ref PRIMARY          PRIMARY        4 dragoni_zfms.eop.nOrderID         1  Using index
1   PRIMARY            eos   eq_ref PRIMARY,nOrderID PRIMARY        4 func                              1  
2   DEPENDENT SUBQUERY eos   ref    nOrderID         nOrderID       4 dragoni_zfms.eo.nUID              1  Using where; Using index; Using filesort

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在您的例子中，不使用mysql而使用php执行某些操作更容易。 我在我的练习案例中看到了当你赢得时间。请尝试将复杂查询划分为几个简单查询。然后使用php脚本执行必要的过滤。 希望能有帮助。

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谢谢

尝试将该子选择更改为联接。可能使用group by并选择MAX会得到与order by DESC LIMIT 1类似的结果。您可以以文本而不是图片的形式提供解释。请显示您的

order\u状态表的定义。相同的别名（eos）用于标识不同的项目（实际上是同一个表，但在不同的上下文中调用了两次）。也许这不是问题，但在调试时使用不同的名称会有所帮助。@我已经以文本形式提供了解释，您能检查一下吗