Name: 在Tableau中建立一個條形圖。使用條形圖比較不同類別的數據 (Build a bar chart in Tableau: Use a bar chart to compare data across categories)
Uploaded: 2021-01-14T09:23:39.000Z
Duration: 2 min 40 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

程度副詞

In this lesson, we would like to create a chart that gives us information about the ratio between reviews left and the number of audio book purchases in a given month.

An important KP I showing us whether people who buy audiobooks leave reviews.

To do that, we'll need to create a few calculated fields.

First, let's create a field which counts the number of ratings, not the sum of all ratings but their count.

It will be much easier if we create this field and use it going forward.

The name of the field we are creating is number of ratings, and I simply need to use the count function.

The next calculated field I would like to create is number of purchases.

We've selected two audio book sales here.

I will create a field called number of purchases, which will contain the number of audio book sales the company made.

Well, the transaction I D code is unique, right?

If we count it, we should obtain the number of sales transactions, which is precisely what we're looking for.

We can create the last calculated field, which will be the ratio between reviews and new purchases.

It is a fairly easy task, given that we've already created the number of reviews and the number of purchases.

All we have to do is divide the two figures, and we'll obtain the measure we want to plot from the very beginning, let's add it to the rose of our visualization.

The result is a pretty nice bar chart, which is a bit too large but still looks meaningful.

It appears that the ratio of ratings two new students was significantly lower in November 2017 and way higher the month before, three times lower.

To be precise, I am sure the firm's business intelligence team would want to have a look at that and analyze what the reason is for this.

Let's quickly edit the title of the horizontal axis two month and save our work.

 In our next lesson, we'll organize the charts we created in a dashboard. 