MySQL：计算两个字段

Question

我有一个看起来像这样的表：

Pizza  ----|| Topping 
====================
Cheese--||    Olives
====================
Ham-----     || Tuna
====================
Cheese-- || Olives
====================
Cheese-- || Tuna
====================

我想获得每种类型的比萨饼的数量，因此在上表中将有一个火腿披萨和2个奶酪披萨（因为奶酪+橄榄重复，应该只计算一次）。基本上，我需要计算每两个相等元素的每一行并按比萨分组。

该查询的结果应为：

Pizza  ----|| Count
====================
Cheese--||    2
====================
Ham-----     || 1
====================

谢谢！

Answer 1

select Pizza, count( distinct Topping) as cnt
from your_pizza_table
group by Pizza
order by cnt desc;

Answer 2

试试这个

SELECT pizza, count(distinct pizza,topping) FROM test GROUP BY pizza;