Rank of Days with an Occurance

[gp10]

Hi community,

Lets say my data are sales, employees and dates.
I would like to create a column where I will have a count of dates whith transactions, that will be irrelevant from the amount of the transactions, but specific for employees.

Every employee has a different working schedule, and they do not work the same amount of days each week, month etc.
I want to able to see how each employee performed based on their working days. So, I would like to create a slicer with options like "First 30 Days", "First 100 Days" etc. In order to do so I need this ranking column.

So this is what I would like to achieve: 

Date Time	Sales ID	Employee Name	Sales Working Date Count
1.1.22 12:00PM	1	John	1
1.1.22 13:00PM	2	Jack	1
1.1.22 13:00PM	3	John	1
1.1.22 14:00PM	4	Mary	1
2.1.22 13:00PM	5	John	2
2.1.22 14:00PM	6	Mary	2
2.1.22 15:00PM	7	Mary	2
3.1.22 11:00AM	8	Jack	2
3.1.22 12:00PM	9	Mary	3
3.1.22 16:00PM	10	Mary	3
4.1.22 11:00AM	11	Mary	4
4.1.22 12:00PM	12	Jack	3
4.1.22 16:00PM	13	Jack	3

I would prefer the best solution for this performance wise either in Power Query or as a calculated column.
In MySQL it could be even better...

[CNENFRNL · Accepted solution]

Adding a date column as a helper column make it much easier; but that's no fun at all. I avoid it on purpose for fun only.

PQ solution,

Caculated Column solution,

Stay tuned for SQL solution after my lunch break ...

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The most concise solution (T-sql),

Bonus solution by powerful Excel formula,

[gp10]

Hi @CNENFRNL,
one more question. If we want to add one more column in the grouping.
For example we rank the days by Employee and Sales, what if we wanted a Store column as well. Meaning different rank for each store.
I have managed to do it in DAX, but having some difficulties in M and SQL.

[gp10]

Legendary stuff @CNENFRNL , thanks a lot, what a reply!
Will test all of them.