August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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｜
133Prep Builder
中的汇总功能
要将总值字段添加到现有数据中，需对汇总的
Group by
部分中的那些内容设置
join
（连接）条件。在这个例子中，连接条件是原始数据集中的项目类型，它与汇总数
据集中的项目类型具有相同的值。
15.5
详细程度计算选项
如果想避免在汇总后重新
join
（连接）数据，可以考虑使用
Level of Detail
（细节程度）
计算。正如第
33
章将介绍的那样，这种类型的计算不会像汇总步骤那样改变数据集
的粒度。与之相反，你可以设置如何汇总，以及将一个度量值汇总到哪个细节程度，
但保持数据集的其余部分不变。因此，此时就不需要重新连接数据集了。
15.6
小结
Prep Builder
中的汇总步骤，与
Tableau Desktop
用户理解的数据汇总方式有很大不同。
改变数据的粒度是数据准备的一个常见方面，因为它使你能够更容易地将数据集连
接在一起，或减少分析期间需要处理的记录数量。如果在
Tableau Desktop
中对数据
进行可视化，必须注意不要对数据源进行过度汇总，因为这可能会影响到该工具的
一些优势功能发挥。具体来说，由于
Tableau Desktop
根据视图内的离散字段汇总数
据──让你可以自由地按想要的方式分析数据，因此除非确实必要，否则不应该汇
总数据，否则有可能会失去这种灵活性。
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.