SQL - How to combine two queries from the same tables into one table with separate columns from each query?

Question

I have a table in a database that is structures as follows:

| date      | app    | action    | response |
|-----------|--------|-----------|----------|
| 9/22/2022 | e-file | launch    | 2        |
| 9/22/2022 | e-file | login     | 3        |
| 9/22/2022 | e-file | edit      | 5        |
| 9/22/2022 | e-file | clicksave | 6        |
| 9/22/2022 | e-file | logout    | 7        |
| 9/28/2022 | cube   | launch    | 3        |
| 9/28/2022 | cube   | login     | 2        |
| 9/28/2022 | cube   | edit      | 7        |
| 9/28/2022 | cube   | clicksave | 8        |
| 9/28/2022 | cube   | logout    | 9        |

I want to achieve this result in order to use this in a grafana table:

| action    | response_e-file | response_cube | e vs cube |
|-----------|-----------------|---------------|-----------|
| launch    | 2               | 3             | 0.33      |
| login     | 3               | 2             | -0.33     |
| edit      | 5               | 7             | 0.40      |
| clicksave | 6               | 8             | 0.33      |
| logout    | 7               | 9             | 0.29      |

The response column will be split out into different columns based on the value in the app column. Additionally, there will a new column performing simple math based on the two response columns.

I'm quite new to SQL and haven't had much luck.

What would the query be to achieve this? Is this even achievable?

Answer 1

We pivot using case-when and then group by action .

select   action
        ,max(case app when 'e-file' then response end)                                                                                             as "response_e-file"              
        ,max(case app when 'cube'   then response end)                                                                                             as "response_cube"   
        ,(max(case app when 'cube' then response end)-max(case app when 'e-file' then response end))/max(case app when 'e-file' then response end) as "e vs cube"
from     t
group by action

action	response_e-file	response_cube	e vs cube
launch	2	3	0.5000
login	3	2	-0.3333
edit	5	7	0.4000
clicksave	6	8	0.3333
logout	7	9	0.2857

Fiddle

Answer 2

You can achieve this by using nested queries and tweaking the following query to fit your use case -

SELECT action, [response_e-file], [response_cube], (response_cube - response_e-file) / response_cube as e_vs_cube FROM (
    SELECT action, col, val FROM (
        SELECT *, 'response_'+app as col, response as val FROM @T
    ) t
) tt

It is unclear on how the e_vs_cube column is calculated since the values seem inconsistent.

For the first 2 rows it seems (response_cube - response_e-file) / response_cube but the others it looks like (response_cube - response_e-file) / response_e-file .