August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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｜
285
实现高级连接
图
32
-
4
：设置多个连接条件，以消除如图
32
-
3
所示的重复数据
要添加第二个条件，可单击
Join configuration
（连接配置）窗格右上角圆圈
中的加号。
32.2
非等价连接条件
在很多情况下，当我们考虑如何将两个数据集连接在一起时，我们会寻找两个数据
集中的共同字段。我们也经常会想到寻找彼此相等的东西。然而，在很多情况下，
286
｜
第
32
章
使用非等价的条件也能发挥很大的作用。我们再来看看
Preppin
’
Data 2020
：第
8
周
挑战赛中的例子。
32.2.1
用连接来过滤数据
有若干周的
Sales
（销售额，见图
32-1
）数据，需要与公司
Profit
（利润）的数值和
数量进行比较（见图
32-2
）。每个星期利润数据集都有一条记录对其进行评估。我
们要只包括那些超过
Profit Minimum
（利润最小值）的周。
只返回超过来自另一个数据集数据的值，这时设置连接条件就会特别方便。需要记
住，返回的数据越少，数据准备所需的处理时间就越少。
在这个例子中，所需的连接条件是，记录的商品价值和数量超过了利润最低预期。
此处使用两个大于或等于的连接条件来设置，如图
32-5
所示。
图
32
-
5
：设置大于或等于的连接条件，将其作为过滤规则
｜
287
实现高级连接
这里实际上使用了四个连接条件。每个数据集的 ...
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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.