php - Check for duplicate rows querying only a substring of the data

Question

I have duplicate images saved in different directories. Because every image location is stored in the database I want to remove duplicate rows of data. I can use this query to look for duplicate image locations in the same directory:

SELECT *
FROM page_additional_images
GROUP BY image_loc
HAVING COUNT(image_loc) > 1

But, it won't work for images in different directories e.g. cars & cars4.

/images/**cars**/hispano-suiza-k6-pictures-and-wallpapers/hispano-suiza-k6.jpg
/images/**cars4**/hispano-suiza-k6-pictures-and-wallpapers/hispano-suiza-k6.jpg

How can I take the query above and look for duplicates ignoring everything before the last "/"?

I want to explode each row by "/" and only query the last element in each array.

Answer 1

据我所知，在 MySQL 中最接近 PHP 风格的爆炸是使用 SUBSTRING_INDEX（delim='/'，带有负数参数，例如 -1 仅获取文件名）： http://dev。 mysql.com/doc/refman/5.0/en/string-functions.html#function_substring-index

Answer 2

你可以给每个条目一个唯一的 id，mysql 可以自动判断是否有重复的条目，并阻止它被查询到数据库中。在 mysql 手册中查找 UNIQUE INDEX