August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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68
｜
第
8
章
我们常用的日期格式是
dd/MM/yyyy
（例如，
25/09/2019
）。
d
代表月份的一天，我
们用
dd
，因为一天可能有两个数字。
M
代表月份，同样使用
MM
，因为月份可能有两
个数字。
y
代表年，你会用
yy
代表年的最后两位数字（例如，图
8-1
中的日期代表
2019
年），或者用
yyyy
代表全年的四位数字。
图
8
-
1
：日期的各个部分
日期部分是区分大小写的。我们用小写的
d
和
y
表示日和年，而用大写的
M
表示月。
这是因为分钟的缩写（当我们有时间和日期时）是小写的
m
，我们需要确保我们所代
表的不同元素之间能够准确区分。
日期可以告诉我们的不仅仅是今天是哪一天，在哪一年哪一个月。工作日、星期和
季度都可以从这个基本的日期格式中确定。例如，
2019
年
9
月
25
日是周三，是在
2019
年第三季度的第
39
周。最新的
BI
工具可以以所有这些方式来剖析日期字段，
但并非总是如此。
8.3
日期查询表
在大多数数据库设置中，通常可以访问一个参照表，该表将以不同的方式剖析同一
个日期。例如，经常会在日期参照表中找到以下一些列：
•
日期。
•
年份。
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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.