SELECT Header.*, ;
       ROUND(SUM(IIF(ChildCondition1,Child.Qty,0)),2) AS Qty1, ;
       ROUND(SUM(IIF(ChildCondition2,Child.Qty,0)),2) AS Qty2, ;
       ROUND(SUM(IIF(ChildCondition3,Child.Qty,0)),2) AS Qty3 ;
  FROM Header ;
  JOIN Child ON Header.HeaderID = Child.HeaderID