FIRSTDATE DAX Function
The FIRSTDATE function returns a table containing a single column and single row with the first date in the current context for the specified column of dates.
DAX Syntax FIRSTDATE(date)
The parameter date is a column containing dates.
Example: We have one table named Sheet1.
The following expression returns the first date in the current context.
DAX
Table = FIRSTDATE('Sheet1'[MyDates])