Calculating the last day of a period, such as a month or a year, is a frequent requirement in data analysis, especially when dealing with financial, sales, or performance data that is often summarized on a monthly or annual basis. The LAST_DAY function simplifies this task by returning the date of the last day of the period that contains the specified date.
The basic syntax for the LAST_DAY function in Snowflake SQL is:
LAST_DAY(<date_or_time_expr>, <optional_date_part>)<date_or_time_expr> is the date or timestamp expression from which you want to find the last day of the period. [<optional_date_part>]: This optional argument allows you to specify the part of the date to consider for the calculation, such as MONTH or YEAR. If omitted, the default is typically MONTH.
For example, if we had a lead that was created mid-January, when we apply the LAST_DAY function for ‘month’ let’s explore the syntax and result:
LAST_DAY ("CreatedDate",'month',) “Month End Date”
RESULT EXAMPLE (assuming Created Date is ‘2024-01-25’)
2024-31-01
What if we wanted to calculate the last day of the year? If your SQL looks like the following, you are on the right track!
LAST_DAY ("CreatedDate",year,) “Year End Date”
RESULT EXAMPLE (assuming Created Date is ‘2024-01-25’)
2024-31-12