MySQL Query外观问题

Question

这是我的查询，我实际想要的是通过最常出现的单词来制作搜索结果顺序，而且单词也可以多于一个单词，但是当输入多个单词时它就会破坏。

SELECT *,
       (LENGTH(`product_name`) - LENGTH(REPLACE(`product_name`, 'apple', ''))) /
       LENGTH('apple') + (LENGTH(`product_name`) - LENGTH(REPLACE(`product_name`, 
       'iphone', ''))) / LENGTH('iphone') + (LENGTH(`product_s_desc`) -     
       LENGTH(REPLACE(`product_s_desc`, 'apple', ''))) / LENGTH('apple') + 
       (LENGTH(`product_s_desc`) - LENGTH(REPLACE(`product_s_desc`, 'iphone',
       ''))) / 
       LENGTH('iphone') + (LENGTH(`product_sku`) - LENGTH(REPLACE(`product_sku`, 
       'apple', ''))) / LENGTH('apple') + (LENGTH(`product_sku`) - 
       LENGTH(REPLACE(`product_sku`, 'iphone', ''))) / LENGTH('iphone') 
       `occurences` 
FROM  `#__virtuemart_products` p, `#__virtuemart_products_".$dblangcode."` l 
WHERE (product_name LIKE '%apple%' OR product_name LIKE '%iphone%' AND 
       product_s_desc LIKE '%apple%' OR product_s_desc LIKE '%iphone%' AND 
       product_sku LIKE '%apple%' OR product_sku LIKE '%iphone%' ) 
ORDER BY `occurences` DESC