August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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292
第
33
章
创建
LOD
计算
正如你所看到的，将数据集连接在一起是数据准备中很常见的任务。但是，有一种
连接的用法，由于它的目的稍有不同而需要强调说明──一种叫作
Appending
（追加）
的技术。在
Tableau
的产品套件中，在
LOD
（
Level of Detail
，详细程度）计算中经
常使用追加，即使你没有意识到正在这样做。
本章将使用
LOD
计算来展示将值追加到你的数据集所带来的便于进行数据分析的
好处。
LOD
计算可能很难学，所以本章将引导你了解
LOD
计算对数据集的实际作用，
以巩固你的理解。
33.1
什么是追加
Appending
（追加）是将一个或多个数据字段添加到现有数据集上。这听起来与连接
非常相似，但我们在添加包含一个常量或一组常量的字段时使用术语
Append
，而不
是在连接操作中建立的多行数据之间的关系。
33.2
通过
LOD
计算来研究追加
由于
Prep Builder
是为
Tableau Desktop
和
Server
准备数据而设计的，因此你们中的
许多人可能会从在
Tableau Desktop
中使用
LOD
计算时就熟悉它们。如果不熟悉，
让我们快速回顾一下。
｜
293
创建
LOD
计算
33.2.1
何时使用
LOD
计算
Tableau
通过在
Tableau Desktop
视图中使用的粒度维度或维度组合来设置度量的汇 ...
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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.