# Time Series - Function and Calculation (AGO, YTD, …)

Time Series functions provide the ability to compare business performance with previous time periods, allowing you to analyze data that spans multiple time periods. For example, time series functions enable comparisons between current sales and sales a year ago, a month ago, and so on.

## List

### Ago

Calculates the aggregated value from the current time back to a specified time period.

For example, Ago can produce sales for every month of the current quarter and the corresponding quarter-ago sales.

### YTD Sale

It means the summation of sales from 1st Jan of the current year to the Current Date. The current Date is kind of a misnomer since its value can vary(can have values like day, month, quarter etc) depending on the granularity. We will understand this while going over these functions in detail.

### QTD Sale

It means the summation of sales from first of first month of the current quarter of the current year to the Current Date.

### MTD Sale

It means the summation of sales from first of the current month to the Current Date.