# Compare records

Source: https://neondeerdata.com/docs/platform/automations/steps/compare-records/

Step · Compare

Compares two sets of records of one object: only in A, only in B, or in both.

## Inputs

| Label         | Key                | Type    | Required | Notes                                                          |
| ------------- | ------------------ | ------- | -------- | -------------------------------------------------------------- |
| Record object | `record_object`    | Object  | Yes      | Variables cannot be wired. The sets appear after it is picked. |
| Set A         | `previous_records` | Records | No       |                                                                |
| Set B         | `new_records`      | Records | No       |                                                                |

## Outputs

| Label       | Key         | Type                  | Always set | Notes                                                            |
| ----------- | ----------- | --------------------- | ---------- | ---------------------------------------------------------------- |
| Only in B   | `added`     | Group: Count, Records | Yes        | `added.count`, `added.records` (list of records)                 |
| Only in A   | `removed`   | Group: Count, Records | Yes        | `removed.count`, `removed.records`                               |
| Differences | `changed`   | Group: Count, Records | Yes        | Items in A or B but not both. `changed.count`, `changed.records` |
| In both     | `unchanged` | Group: Count, Records | Yes        | `unchanged.count`, `unchanged.records`                           |

## How it behaves

- Set comparison on the record ID (lowercased). Duplicates count once; order is ignored. Always takes the single outcome.

## Errors

Fails when

- Neither Set A nor Set B is wired. Pick a Record object and wire at least one set.
- No wired entry can be read as a record. The step fails rather than report no changes.
- A wired record belongs to a different object than Record object. Wire records of that object, or change Record object to match.

For errors that every step can return, see [Troubleshooting](https://neondeerdata.com/docs/platform/automations/troubleshooting/).

## Example

Find which people were linked to or unlinked from a deal, comparing the list before and after an update.

**Example inputs**

| Input         | Value                 |
| ------------- | --------------------- |
| Record object | People                |
| Set A         | Priya Shah, Tom Reyes |
| Set B         | Priya Shah, Lena Park |

**Example outputs**

| Output      | Value                         |
| ----------- | ----------------------------- |
| Only in B   | Count 1: Lena Park            |
| Only in A   | Count 1: Tom Reyes            |
| Differences | Count 2: Tom Reyes, Lena Park |
| In both     | Count 1: Priya Shah           |

A record from another object in either set fails the step.