mysql - SQL 按结果计数排序

Question

我有一个包含如下数据的表格:

Meal ID   |   Child    |  Fruit

1              Child A     Apple
2              Child B     Orange
3              Child A     Banana
4              Child A     Orange
5              Child C     Banana
6              Child A     Banana
7              Child C     Banana
8              Child A     Banana

我需要根据所吃的水果对结果进行排序，从高到低，例如如果搜索查询是香蕉，结果将显示如下:

Banana Eaters (Highest to Lowest)

Child   |   Number of Bananas eaten

Child A     3
Child C     1

我会开始:

 $sql = "SELECT * FROM meals WHERE Fruit = 'Banana'";

但我如何将独特的个人香蕉食者分类为他们自己的条目，然后按吃得最多的人对结果进行排序？

Answer 1

按 child 分组并使用条件聚合:

select child, sum(fruit = 'Banana') `Number of Bananas eaten`
from meals
group by child
order by `Number of Bananas eaten` desc 

如果您想排除没有任何香蕉的 child :

select child, sum(fruit = 'Banana') `Number of Bananas eaten`
from meals
group by child
having `Number of Bananas eaten` > 0
order by `Number of Bananas eaten` desc 

参见 demo .