Use Neon branching for testing

We previously ran a DELETE query on the shoes table to remove duplicates. However the query was wrong because it didn’t specify all the criteria. Here how the query should have been written:

DELETE FROM shoes a USING shoes b
WHERE a.id > b.id
AND a.brand = b.brand
AND a.model = b.model
AND a.description = b.description
AND a.color = b.color

Since a DELETE is a potentially destructive operation, it is recommended to test the query first to make sure it works as intended. You can easily do this on a new branch before trying it on your backup branch.

Navigate to the Branches page and click on the New Branch button to create a new branch.

This time, create a test branch from Head with the most up-to-date state of the database and specify backup as parent.

Run remove duplicates query on backup branch

Navigate to the SQL Editor, select the test branch and run the query to remove duplicates.

DELETE FROM shoes a USING shoes b
WHERE a.id > b.id
AND a.brand = b.brand
AND a.model = b.model
AND a.description = b.description
AND a.color = b.color

Next, run a SELECT model, color FROM shoes query to verify the result.

| # |         model        | color                                          |
|---|----------------------|------------------------------------------------|
| 1 | Air Zoom Alphafly    | Scream Green/Bright Crimson/Honeydew/Black     |
| 2 | Air Zoom Alphafly    | Total Orange/Bright Crimson/Ghost Green/Black  |
| 3 | ZoomX Vaporfly       | Scream Green/Bright Crimson/Honeydew/Black     |

You managed to remove duplicates from the shoes table. You can now safely apply the same query to the parent branch.

Conclusion

Congratulations. You completed the Neon Tutorial. Here is a recap of what was covered:

• You created a Neon project.
• You create a table and inserted data using the Neon SQL Editor.
• You learned about Neon's database branching feature and how you can use it to recover lost data and test potentially destructive queries before before running them in production.