# Join datasets
The Join step allows you to combine two datasets listed in the dataHub to bring columns from the former into the latter, matching rows based `on` columns correspondance
### Step parameters
* `Select a dataset to join (as a right dataset)` **column(string)\***: Select a dataset to join as the right dataset.
* `Select a join Type` **dropdown(string)\***`:` Choose from "left", "inner", or "left outer" join.
* `left`: will keep every row of the current dataset and fill unmatched rows with `null` values,
* `left outer` :
* `inner`: will only keep rows that match rows of the joined dataset.
* `Join based on columns:`specify 1 or more column couple(s) that will be compared to determine rows correspondance between the 2 datasets. The first element of a couple is for the current dataset column, and the second for the corresponding column in the right dataset to be joined. If you specify more than 1 couple, the matching rows will be those that find a correspondance between the 2 datasets for every column couple specified (logical ‘AND’).
### Example
**Input**
