Can you display a column value using CASE

I am selecting several columns from TABLB1.

One column (POST_DATE) I want to display as '9999-99-99' only if the (DB2) value is '0001-01-01', otherwise I want it to display the actual DB2 value.

This works fine:

  ,CASE 
    WHEN POST_DATE = '0001-01-01' THEN '9999-99-99' 
    ELSE  'NOT 0001-01-01'  END  AS POSTING_DATE

This does NOT work:

  ,CASE 
    WHEN POST_DATE = '0001-01-01' THEN '9999-99-99' 
    ELSE  POST_DATE  END  AS POSTING_DATE

Is there a way to do this in SPUFI?