Which function can calculate the difference in days between two dates?

The function that calculates the difference in days between two dates is DATDIF(). This function is specifically designed to compute the difference in days or other intervals, making it straightforward for users to determine how many days lie between two date values within SAS. When using DATDIF(), you typically provide two date values and specify that you want the result expressed in days, allowing for an accurate and user-friendly calculation of the number of days separating those dates.

In contrast, the INTNX() function is generally used for shifting dates by a specific interval, such as moving forward or backward to the next month or year. The DAY() function is used to extract the day of the month from a date value, not to calculate differences. The WEEKDAY() function returns the day of the week for a given date, which is also unrelated to calculating the difference in days between dates.