As an analyst, you may often receive data from multiple sources, and in order to draw a conclusions, you need to combine data in a single dataframe.

If you are familiar with SQL, you may heard about different types of joins (like, left, right, or inner). As an example, we will use two dataframes with pregenerated data (id, name, surname, age, and height (in cm)).

To get started with joins, first we need to note that any kind of join require some key field that will be used for comparison between tables. These values should be unique across each table.

For instance, it's common practice to join tables by some id field.