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@ezmac13  if the math works, don't change.

To solve problems like this, I usually pop open Excel and figure it out there because it's super easy to find 'excel equivalent in mysql' 

alternatively, if you used an article like https://stackoverflow.com/questions/6944055/how-do-i-get-the-first-day-of-the-week-of-a-date-in-mysql then be careful that you refactor for simplicity

since subDate and date_add do the same thing, I would just use date_add to make my code a little easier to read.

with date_add(...) indicate the interval you're assuming (day)

have a closer look at WEEKDAY(DATE_ADD(`DATE`,-1))-1, off the top of my head I don't recall if weekday does zero based indexing or not (0 - 6 vs 1-7)

WHAT I WOULD DO.

I would build this calc into a date dimension table.  and then JOIN the date dimension to my fact table.  This way, when the business changes their mind next week, OR when different people have different ways of slicing days and weeks, you don't have to maintain a ton of cards and beast modes.