03.course-group-by-having-count【GROUP By、Having和COUNT】
Introduction 介绍 Now that you can select raw data, you’re ready to learn how to group your data and count things within those groups. This can help you answer questions like: 现在您可以选择原始数据，您已经准备好学习如何对数据进行分组并对这些组中的内容进行计数。 这可以帮助您回答以下问题： How many of each kind of fruit has our store sold? 我们店每种水果销售了多少？ How many species of animal has the vet office treated? […]