August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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360
｜
第
39
章
图
39
-
13
：只保留合同日期范围内的日期的计算方法
Prep Builder
的清理步骤中的过滤器必须返回一个布尔结果。符合条件集的记录（即
返回
True[
真
]
值的记录）将保留在数据集中。那些不符合过滤器中的条件设置的
记录——返回
False
（假）的记录将从流程中删除，每份合同的收入每月留下一行记
录（见图
39-14
）。
图
39
-
14
：显示数据支撑的正确结果的行数
39.5
新数据支撑技术
虽然传统的技术是可行的，但它确实有一些缺点。其中最突出的是，数据支撑中的
日期列表必须及时维护和更新。这听起来没有太大问题，但这意味着要记住文件的
保存位置，记住更新它，并确保你的同事也知道在哪里以及如何做这件事（以防你
离开后无法继续维护）。
几年前，当
Bethany Lyons
在
Tableau
会议上介绍了
Tableau Desktop
中的一项新技
术时，这一切都改变了。她通过要求一个需要支撑的数据集为每个日期创建额外记
录的逻辑，采用这个方法解决了前述许多问题。和刚才详细介绍的传统方法一样，
新技术也利用了不同的日期计算，但它的不同之处在于，这些日期都是由简单的整
｜
361
支撑你的数据
数创建的。在移动供应商的例子中，最久的合同时间跨度是
24
个月，所以数据支撑
需要一列从
0
到
23
的整数（见图
39-15 ...
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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.