mysql desc 对我不起作用

Question

它应该列出一个列表，并在顶部列出最高百分比..但它没有 https://gyazo.com/ecde864ef09115b8b119eba8a39ecd68这是我运行时的图片

这里是代码。怎么了？

$sql = "SELECT band, concat(round(sum(punten) *100 /
(SELECT sum(punten) FROM bands)) , \"%\") AS percent
FROM bands
WHERE punten>0
GROUP BY band 
ORDER BY percent DESC;";

Answer 1

百分比列是一个字符串，因此它们按字典顺序排序(例如，8 被视为大于 26，因为“8”在“2”之后)。相反，您可以在连接之前对数字部分进行排序。这可以通过当前查询来完成，但是将总的 punten 增加到子查询会更优雅:

SELECT     band, CONCAT(ROUND(band_punten) * 100 / total_punten), '%') AS percent
FROM       (SELECT   band, SUM(punten) AS band_punten
            FROM     bands
            WHERE    punten > 0
            GROUP BY band) a
CROSS JOIN (SELECT SUM(punten) AS total_punten FROM bands) b
ORDER BY   band_punten DESC