SQL Query添加唯一字符串出现次数

Question

例如，如果我正在创建一个披萨商店数据库，它将看起来像这样

Answer 1

SELECT pizza_type, COUNT(*) as 'NumberOrdered'
FROM table
GROUP BY pizza_type

Answer 2

查看COUNT（）函数和GROUP BY

select pizza_type, count(*) as NumberOrdered
from orders
group by pizza_type