mysql - カウントを追加し、4 つの INNER JOIN と 2 つの LEFT JOIN を含む派生クエリをクリーンアップ/合理化する方法

Question

私は MySQL で派生クエリを使用するのが初めてで、2 つの点で問題があります。

1) t1.dCount を参照して、各 optionId の xcart_images_D.productId の数をカウントするにはどうすればよいですか?

2) このクエリの派生 SELECT を合理化するにはどうすればよいですか? (現在、このクエリの実行には 45 秒かかります)

 SELECT xp.productid, xp.product, xc.classid, xco.optionid, xco.option_name, xiW.id, xiW.image_path, t1.dCount
 FROM xcart_products xp
 INNER JOIN xcart_variants xv ON xp.productid = xv.productid
 INNER JOIN xcart_variant_items xvi ON xv.variantid = xvi.variantid
 INNER JOIN xcart_class_options xco ON xvi.optionid = xco.optionid
 INNER JOIN xcart_classes xc ON xco.classid = xc.classid AND xc.class = 'COLOR'
 LEFT JOIN xcart_images_W xiW ON xiW.id = xvi.variantid
 LEFT JOIN (
 SELECT COUNT(xiD.optionid) as dCount 
    FROM xcart_products xp2
    INNER JOIN xcart_classes xc2 ON xp2.productid = xc2.productid AND xc2.class = 'Color'
    INNER JOIN xcart_class_options xco2 ON xc2.classid = xco2.classid
    LEFT JOIN xcart_images_D xiD ON xiD.optionid = xco2.optionid
 ) as t1 ON xiW.id = xvi.variantid
 GROUP BY xco.optionid
 ORDER by xp.product DESC

これはカウントの作業バージョンですが、派生した選択はありません-

SELECT xp.productid, xp.product, xc.classid, xco.optionid, xco.option_name, xiD.image_path, xiD.path_on_server, count(xiD.optionid) as cnt
    FROM xcart_products xp
    INNER JOIN xcart_classes xc ON xp.productid = xc.productid AND xc.class = 'Color'
    INNER JOIN xcart_class_options xco ON xc.classid = xco.classid
    LEFT JOIN xcart_images_D xiD ON xiD.optionid = xco.optionid
    GROUP BY xp.product, xco.optionid
    ORDER by xp.product DESC

必要な場合は、ここに DB レイアウトを示します -

+ xcart_products
    - productid*
    - product
+ xcart_variants
    - variantid*
    - productid (xcart_products.productid)
+ xcart_variant_items [bridge table]
    - optionid*
    - variantid (xcart_variants.variantid)
+ xcart_classes
    - classid*
    - productid (xcart_products.productid)
    - class
+ xcart_class_options
    - optionid*
    - option_name
    - classid (xcart_classes.classid)
+ xcart_images_W
    - imageid*
    - id (xcart_variants.variantid)
    - image_path
+ xcart_images_D
    - imageid* [not relational with xcart_images_W.imageid]
    - id (xcart_products.productid)
    - optionid (xcart_class_options.optionid)

* Primary Key
() relational data
[] notes