# Joining two series

## Intro

One transformation you can achieve with formula language is to combine two series, creating one longer series. This is useful when you work with historical data that you want to add to a current series. In this tutorial, you will see how to use the ‘Join’ formula and its variations.

In this example, we have two Indian GDP series (innaac1015 and innaac0109), one that ends in 2014 and another that starts in 2011. Our aim is to combine these series. The solution is to use the ‘Join’ formula. This formula has a few different variations depending on what we want the resulting series to be.

## Summary

The Join formula with all its variations is a powerful tool for series transformation. The key is to get familiar with them so that you will be able to use the desired one for each case.

To learn more about Formulas in Macrobond have a look at these articles: Formula.