In PySpark, the function months_between() is used to calculate the number of months between two date or timestamp columns. It returns a float representing the difference, where the integer part is the number of full months, and the decimal part represents the fractional months.
Syntax: -
from pyspark.sql.functions import months_between
# months_between(end_date, start_date)
If start_date is later than end_date, months_between() will return a negative value indicating the difference in reverse.
Conclusion:
months_between() is useful when you need to calculate the exact difference in months between two date or timestamp columns in PySpark.
While PySpark does allow months_between() and datediff() to work directly on string columns in some cases (when the format is correct), explicitly converting the strings to DateType is a more robust and reliable approach.