你需要把价格和价格比较一下。因此，一种方法是：

SELECT b.art, b.price
FROM books b
WHERE b2.price = (SELECT b2.price
                  FROM books b2
                  ORDER BY REPLACE(REPLACE(b2.price, ',', ''), '.', '') + 0 DESC
                  LIMIT 1
                 );

您应该将值存储为 decimal / numeric 类型 . 表示有小数部分。我不建议删除它，因此：

WHERE b2.price = (SELECT b2.price
                  FROM books b2
                  ORDER BY REPLACE(b2.price, ',', '') + 0 DESC
                  LIMIT 1
                 );

这将显式转换替换为隐式转换——因为mysql对具有 CAST .
最后，也可以使用窗口函数来处理：

select b.*
from (select b.*,
             rank() over (order by REPLACE(b2.price, ',', '') + 0 desc) as seqnum
      from books b
     ) b
where seqnum = 1

当您强制转换为整数时，请使用 SIGNED 或者 UNSIGNED 作为目标。

SELECT art, price FROM books 
WHERE price = (SELECT MAX(CAST(REPLACE(REPLACE(price, ',', ''),'.','') AS SIGNED)) 
FROM books)

应该将数值存储为数字而不是字符串。