I am using Teradata and there is a scenario which I am not sure how to achieve it using sql query. I have a table with data as given below. The table is grouped based on the columns GP,Key1,Key2 and Key3. Now my requirement is that, I need to populate the start date from the column process date, for few of the ID.

|GP |ID |start date |process date |Key1 |key2 |key3|
:—-| :—-:| :—-:| :—-| :—-:|:—-:|:—-:|
|W1 | W003 | Current_Date |2023-04-24| 1asd| 345| 456|
|W1 | W004 | |2024-08-20| 1asd| 345| 456|
|W1 | W005 | |2024-08-21| 1asd| 345| 456|
|W1 | W0010| |2024-08-22| 1asd| 345| 456|
|W1 | W0120| |2024-08-23| 1asd| 345| 456|
|W1 | W0015| |2024-08-24| 1asd| 345| 456|
|W1 | W0016| |2024-08-25| 1asd| 345| 456|
|W2 | W234 | Current_Date |2021-05-27| 2def| 111| 222|
|W2 | W345 | |2022-03-21| 2def| 111| 222|
|W2 | W456 | |2023-03-21| 2def| 111| 222|
Now the case here is, in the column ID for the value W004 and W005, I need to populate start date as process date from W003.

Similar way in the column ID for the value W0010,W0120,W0015 and W0016 , I need to populate start date as process date from W005

When it comes to the ID W345 and W456, the start date needs to populated with W234 process start date.

Result table should look as below

I know we can do join with the same table multiple time and try to achieve this, but just thinking is there anyway we can achieve it using a single query. Please note that the connection to IDs which need to populated for start date and from ID where we take the value wont change. For ex. W004 and W005 always take the value from W003 , like that W0010,W0120,W0015 and W0016 always take value from W005