MAXA Function
Returns the largest value in a column. Logical values and blanks are counted.
The MAXA function takes as argument a column, and looks for the largest value among the following types of values:

Numbers

Dates

Logical values, such as TRUE and FALSE. Rows that evaluate to TRUE count as 1; rows that evaluate to FALSE count as 0 (zero).
Empty cells are ignored. If the column contains no values that can be used, MAXA returns 0 (zero).
If you do not want to include logical values and blanks as part of the calculation, use the MAX function.
The following example returns the greatest value from a calculated column, named ResellerMargin, that computes the difference between list price and reseller price.
=MAXA([ResellerMargin])
The following example returns the largest value from a column that contains dates and times. Therefore, this formula gets the most recent transaction date.
=MAXA([TransactionDate])