How do I incorporate this CASE into my SELECT

Here's my current SELECT:

select RID from tasks_accomplishments where CREATED_DATE <='{$asof}'
and  t.PROJECT IN (select DISTINCT t.PROJECT 
FROM tasks t 
JOIN task_metrics tm ON t.ID=tm.RID 
JOIN resources r ON t.PROJECT=r.PROJID
JOIN projects p ON p.ID=t.PROJECT
where r.USER_ID={$user_id}
and r.ROLE IN ('INTDM', 'INTLEAD','INTOWN')
and p.ACTIVE=1)) 

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The problem is the very first line. I can't use CREATED_DATE. Instead, I have to use one of four values:





I'm going to use the value that's defined by the value in the EXPECTED_PHASE column...



...which in this case is DEPLOY. So, I need go grab "2020-02-08."

How?

I wrote this as part of another SELECT:

case when (SELECT EXPECTED_PHASE FROM task_metrics where RID = t.ID) = 'DEPLOY'
      then (select DEPLOY_START_DATE from task_metrics where RID = t.ID)
   when (SELECT EXPECTED_PHASE FROM task_metrics where RID = t.ID) = 'BUILD'
      then (select BUILD_START_DATE from task_metrics where RID = t.ID)
   when (SELECT EXPECTED_PHASE FROM task_metrics where RID = t.ID) = 'DEPLOY'
      then (select DEPLOY_START_DATE from task_metrics where RID = t.ID)
   when (SELECT EXPECTED_PHASE FROM task_metrics where RID = t.ID) = 'ARCH'
      then (select ARCH_START_DATE from task_metrics where RID = t.ID)
   when (SELECT EXPECTED_PHASE FROM task_metrics where RID = t.ID) = 'TEST'
      then (select TEST_START_DATE from task_metrics where RID = t.ID)

...but how would I incorporate that into the SELECT that I've got above?

Hit me!