X Grouping allows you to flip how the data is displayed. The default "Group by Keys" will render the table matching the original source and in a graph the Keys will form the legend. If "Group by Labels" is used, the keys and labels gets swapped and in a graph the labels will form the legend.
In this example dataset:
| Size | Red | Green | Blue |
|---|---|---|---|
| Small | 5 | 10 | 15 |
| Medium | 25 | 30 | 35 |
| Large | 50 | 60 | 70 |
Group by keys would result in the same table being outputted.
If you were to use Group by labels the rendered table would look like this:
| Size | Small | Medium | Large |
|---|---|---|---|
| Red | 5 | 25 | 50 |
| Green | 10 | 30 | 60 |
| Blue | 15 | 35 | 70 |