Question

I have a table like this.

ID  Name      Source ID
1   Orange       0
2   Pear         0
3   Apple        0
4   Orange       0
5   Apple        0
6   Banana       0
7   Orange       0

What I want to do is:

• For the records with FIRST occurrence of “Name”, I want to update the “Source Id” with the “Id” value
• For the records with SECOND and CONSECUTIVE occurrences of “Name”, I want to update the “Source Id” with the “Id” value of the FIRST occurrence

So, the table should be updated as follows:

ID  Name      Source ID
1   Orange       1
2   Pear         2
3   Apple        3
4   Orange       1
5   Apple        3
6   Banana       6
7   Orange       1

How can I do it in SQL (Oracle to be in particular, but I’m fine with General SQL as well) …

Thanks!

Answer 1

Something like this should get you what you want:

update table a
set source_id = (
    select min(id)
    from table b
    where b.name = a.name
);