[RESOLVED] SQL Question

[belebala]

Anyone could help me to create the following sql update statement?

Here is my table:

Primary Key | Foreign Key | Description
1 | 1 | a
2 | 1 | null
3 | 2 | b
4 | 2 | null
5 | 3 | c
6 | 3 | null

I would like to copy the data on Description column if the Foreign Key is the same. Here is the outcome I would like to have:
Primary Key | Foreign Key | Description
1 | 1 | a
2 | 1 | a
3 | 2 | b
4 | 2 | b
5 | 3 | c
6 | 3 | c

Thanks.