How to create a funnel visual bar chart in Tableau by creating a calculated field using an existing column in the data source

Question

A column called 'Pool' exists in my data source.

There are roughly three values in the column:

|  Pool  |
|   B    |
|   C    |
|   B    |
|   A    |

As you can see, there are three different values: A, B, and C. I'd want to make a funnel, which is simply a bar chart that will compute and count each of those three numbers in the entire column. I know I can't just put the column in the sheet since I also want a fourth bar that counts all of the values as a "All" category.

As a result, having a visual that says (but this is in tabular form to help illustrate what I mean)

All | 40
A   | 5
B   | 20
C   | 15

Answer 1

Please find a possible solution in fiddling.

You could combine two results to get the COUNT for each of your values and one COUNT for all of your samples by using UNION.

(SELECT Pool, COUNT(Pool) AS your_count
FROM your_table
GROUP BY Pool)
UNION
(SELECT 'ALL', COUNT(*) AS your_count
FROM your_table)
ORDER BY your_count DESC