Find oldest task for each user

Hi,

I have 2 tables - DIM_Users and FACT_Tasks with fields as per below:

DIM_Users:

- User name

FACT_Tasks

- Task ID

- Close Date

I am trying to identify the oldest (resp. the first) closed task from FACT_Tasks table for each user in table DIM_Users. Could you please help me? The result should be new column in table DIM_Users. If there is no closed task for user yet, the field should be empty.

Thank you

IvanS