My suggestions for this feature:

Calendar date ranges:

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This date range would be from the start of the current year/month to now. E.g. 01-01-2019 to now.

- Customer - Total Spent This Calendar Year

- Customer - Total Spent This Calendar Month

Rolling date ranges:

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E.g. between now and 12 months ago. Ideally the time frame would be variable but this would require additional rule fields that would complicate the UI.

- Customer - Total Spent In Last 12 Months

- Customer - Total Spent In Last 6 Months

- Customer - Total Spent In Last 30 days

OR

- Customer Total Spent In Last X Months/days

Other useful rules:

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- Customer- Total Spent Last Calendar Year

- Customer- Total Spent Last Calendar Month

Hoping to see this as a feature soon. I have over 30 sites that would use this immediately