DATE Returns the specified date in datetime format.
Syntax
DATE(year, month, day)
Parameters
year – A number representing the year.
The value of the year argument can include one to four digits. The year argument is interpreted according to the date system used by your computer.
Dates beginning with March 1, 1900 are supported.
If you enter a number that has decimal places, the number is rounded.
For values greater than 9999 or less than zero (negative values), the function returns a #VALUE! error.
If the year value is between 0 and 1899, the value is added to 1900 to produce the final value. See the examples below. Note: You should use four digits for the year argument whenever possible to prevent unwanted results. For example, using 07 returns 1907 as the year value.
month – A number representing the month or a calculation according to the following rules:
If month is a number from 1 to 12, then it represents a month of the year. 1 represents January, 2 represents February, and so on until 12 that represents December.
If you enter an integer larger than 12, the following computation occurs: the date is calculated by adding the value of month to the year. For example, if you have DATE( 2008, 18, 1), the function returns a datetime value equivalent to June 1st of 2009, because 18 months are added to the beginning of 2008 yielding a value of June 2009. See examples below.
If you enter a negative integer, the following computation occurs: the date is calculated subtracting the value of month from year. For example, if you have DATE( 2008, -6, 15), the function returns a datetime value equivalent to June 15th of 2007, because when 6 months are subtracted from the beginning of 2008 it yields a value of June 2007. See examples below.
day – A number representing the day or a calculation according to the following rules:
If day is a number from 1 to the last day of the given month then it represents a day of the month.
If you enter an integer larger than last day of the given month, the following computation occurs: the date is calculated by adding the value of day to month. For example, in the formula DATE( 2008, 3, 32), the DATE function returns a datetime value equivalent to April 1st of 2008, because 32 days are added to the beginning of March yielding a value of April 1st.
If you enter a negative integer, the following computation occurs: the date is calculated subtracting the value of day from month. For example, in the formula DATE( 2008, 5, -15), the DATE function returns a datetime value equivalent to April 15th of 2008, because 15 days are subtracted from the beginning of May 2008 yielding a value of April 2008.
If day contains a decimal portion, it is rounded to the nearest integer value.
Return Value
Returns the specified date (datetime).
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference