Nachtrag

[Ferris]

Mein Versuch sieht jetzt so aus.
Ist das korrekt?

SELECT  
    PRODUCTS.id,  
    PRODUCTS...andere Angaben...,  
    COLORS.colorname,  
    COLOR_SIZE_RELATION.price,  
    PRODUCT_DETAILS.size,  
    PRODUCT_DETAILS...andere Angaben...,  
FROM  
    PRODUCTS  
LEFT JOIN  
    PRODUCT_DETAILS  
ON PRODUCT_DETAILS.productid = PRODUCTS.id  
LEFT JOIN  
    COLORS  
ON COLORS.id = PRODUCTS.colorid  
LEFT JOIN  
    (COLOR_SIZE_RELATION  
    INNER JOIN  
        SIZES  
    ON SIZES.id = COLOR_SIZE_RELATION.sizeid  
    )  
ON COLOR_SIZE_RELATION.colorid = PRODUCTS.colorid  
AND SIZES.size = PRODUCT_DETAILS.size  
WHERE  
    PRODUCTS.id = '1'