Query Sorting Records First Entry By Group

Query Sorting Records First Entry By Group

  2. SELECT
  3. "IORef",
  4. "PaymentDate",
  5. SUM("FCIRecognition")
  6. FROM  "Dave Live - Income Details" 
  7. GROUP BY "IORef",
  8.  "PaymentDate" 

I wrote the above simple select query - I would like the result to be that for the 'IORef' the earliest date for each 'IORef' is only displayed. So for example, using the results below only row 1 and 11 would appear 

IOB00000004 - 2016-01-28 35.32
IOB00000009 - 2016-01-22   0.51

I have 1000's of rows that I would like the earliest instance of the 'IORef' to only appear in the results - can someone please help me with the SQL I need to use to achieve the desired result?