Question

Due to a bug in my application a table that was built to carry daily records of each delivery period, was populated many times.

Lets say I have a delivery from 1st of June to 5 of June. My table should be populated with 5 records, one for each day. Now, I have havoc because I have many “batches” of the same content.

The table layout is as:

dummy_id       -- identity column
delivery_id    -- id of the delivery
on_date        -- the day
charge         -- the daily cost

Is there an elegant way to keep only the first batch of records and delete the batches that were inserted by mistake for all the deliveries?

Answer 1

To delete all dupes for delivery_id, on_date, charge keeping the one with the lowest dummy_id

;WITH cte
     AS (SELECT ROW_NUMBER() OVER (PARTITION BY delivery_id,
                                                on_date,
                                                charge
                                       ORDER BY dummy_id) RN
         FROM   YourTable)
DELETE FROM cte
WHERE  RN > 1