表更新后，Mysql返回空结果

Question

我有一个包含产品代码的表，在我的情况下，它被称为unic和产品类别，称为CatText表，它自称为sc_products。另一个名为t26_replacebleitems的表包含其中2个产品代码产品本身称为unicitem，并替换为unicreplacement。我这样询问他们：

SELECT 
    unicitem, unicreplacement, 
    sc_products.product_code, sc_products.productID,    
    sc_products.brief_description_ru, sc_products.name_ru, 
    price.postavchik as suupplier, sc_group_discounts.`action`, 
    sc_group_discounts.procent, price.Price as Price, price.in_stock, price.supplier 
FROM 
    sc_products 
LEFT OUTER JOIN 
    t26_replaceable_items ON (sc_products.unic = t26_replaceable_items.unicreplacement) 
LEFT OUTER JOIN 
    sc_group_discounts ON (sc_products.item_group = sc_group_discounts.item_group) 
LEFT JOIN 
    price ON (sc_products.product_code = price.item) AND (sc_products.suupplier=price.postavchik) 
WHERE 
    t26_replaceable_items.unicitem = 'maslo1' 
    AND sc_products.CatText = 'nut' 
    AND CASE 
           WHEN price.Price is null 
              THEN price is null 
              ELSE price.Price = (SELECT MIN(price.Price) 
                                  FROM price 
                                  WHERE price.unic = unicreplacement) 
        END 
GROUP BY 
    productID 
ORDER BY
    isnull (price.Price), price.Price ASC

在我更改一个产品的类别之前它工作正常，但现在它没有返回任何结果。可能存在具有相同代码和不同类别的产品。我该怎么办？