> ## Documentation Index
> Fetch the complete documentation index at: https://docs.superjoin.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Derived Columns Date Functions

> This section covers date-related functions for calculating time differences, extracting date components, and working with the current date. These functions are useful for managing billing cycles, tracking subscription durations, and analyzing transaction trends over time.

### **DATEDIF (Start Date, End Date, Unit)**

* **Syntax**: **`DATEDIF(start_date, end_date, "unit")`**
* **About**: Calculates the difference between two dates in days, months, or years.
* **Example**: To find out how many months a subscription has been active, use **`DATEDIF(activated_at, today(), "M")`** to get the total number of months between the start date and today.

### **EOMONTH (Start Date, Months)**

* **Syntax**: **`EOMONTH(start_date, months)`**
* **About**: Returns the last day of the month a specified number of months away from the start date.
* **Example**: To find the end date of the current billing cycle, use **`EOMONTH(today(), 0)`** to get the last day of the current month.

### **MONTH (Date)**

* **Syntax**: **`MONTH(date)`**
* **About**: Extracts the month from a given date as a number between 1 (January) and 12 (December).
* **Example**: To categorize transactions by month, use **`MONTH(transaction_date)`** to convert a date to a month number.

### **YEAR (Date)**

* **Syntax**: **`YEAR(date)`**
* **About**: Extracts the year from a given date as a four-digit number.
* **Example**: To filter data from the current year, compare **`YEAR(due_date)`** with **`YEAR(today())`** to check if the years match.

### **TODAY (Current Date)**

* **Syntax**: **`today()`**
* **About**: Returns the current date, with no time component.
* **Example**: To check if a subscription is due today, compare **`today()`** with the **`next_billing_at`** date to trigger an alert if they match.