Transformations

Any saved chart querying on event A continues to do so after the merge. However, the chart doesn't automatically switch from event A to event C. For charts created after the merge, neither event A nor event B appears in the chart dropdown; only event C appears.

You can't bulk update charts in Amplitude. Try adding all charts that still use the old events (in this example, events A and B) to a dashboard. Use Find & Replace to swap those events for event C, then click Save onto Charts > Update existing charts.

Saved charts don't automatically switch to a different event property after a transformation. Each chart keeps querying the property you saved with it until you edit the chart.

After the transformation, chart dropdowns only show the merged or target property. You can't create new charts that still query the old, untransformed property names.

How you update existing charts depends on how you merged properties:

• You merged into a new event property C: Update every saved chart that still queries event property A or B. For example, edit each chart and select event property C in the chart controls. You can also add those charts to a dashboard, use Find & Replace to swap the old properties for property C, then click Save onto Charts > Update existing charts.
• You merged into an existing event property (for example, you map both A and B into property A instead of creating a new name): Update any saved chart that still queries a source property you dropped. Charts that already query the target property don't need changes, because they already use the merged property.

That depends on how you created event C in the first place.

• If you merged event A and event B into event C: After refresh, the chart’s user/event totals drop to zero.
• If you merged event A and event C into event C: After refresh, the chart queries the source event C.

Amplitude doesn't support transformations on transformations. If you want this capability, submit a feature request.

Event C is a merged event composed of source events A and B. Can I view event A and event B separately, then event C starting at the date of the transformation? Transformations apply retroactively, so that isn't possible.

Use this example: For one instance of event A, you send the event property event prop = true; for another instance of event A, you send the event property event_property = false. You then merge both event properties into EVENT PROPERTY.

In this situation, when you query on event A and group by EVENT PROPERTY, this user appears twice. You see one data point for the true value and one for false.