I have a truantday table that has students who has absent, each row is one student, one truant day starting from beginning of school year to current date.I would like to find out in every past 30 days(a month) the students has 2 days absent, or 3 days absent.These are the any 30 days that starting from the student has first truant date and the last truant date in this school year, during this period, any 30 days.Thanks
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