DAY(...)=MAX(...)
Checking if a date is maximum for all dates for the same month
Used Functions
Category: Date and time
Converts a serial number to a day of the month
Syntax
DAY(serial_number)
Practice DAY Formula at Sheetzoom
DAY formula at Microsoft helpCategory: Statistical
Returns the maximum value in a list of arguments
Syntax
MAX(number1, [number2], ...)
Category: Date and time
Converts a serial number to a month
Syntax
MONTH(serial_number)
Category: Date and time
Converts a serial number to a year
Syntax
YEAR(serial_number)
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The formula first collect the year and month information from the data and then the corresponding date as an array. That array is used to find the max for the month and then it is compared to respective cell for TRUE or FALSE results.