A、SELECT s.AgentName,SUM(ISNULL(o.OrderTotal,0.00))AS SumOrderTotal FROM SalesAgent s JOIN OrderHeader o ON s.AgentID = o.AgentIDWHERE o.OrderDate BETWEEN @FromDate AND  @ToDate  GROUP BY  s.AgentName B、SELECT s.AgentName,SUM(ISNULL (o.OrderTotal,0.00))AS SumOrderTotal  FROM SalesAgent s JOIN  OrderHeader o ON s.AgentID = o.AgentIDWHERE o.OrderDate BETWEEN @FromDate AND @ToDate  AND o.OrderTotal >= 2000  GROUP BY s.AgentName C、SELECT s.AgentName, SUM(ISNULL (o.OrderTotal,0.00))AS SumOrderTotal FROM SalesAgent s JOIN OrderHeader o ON s.AgentID = o.AgentID WHERE o.OrderDate BETWEEN @FromDate AND @ToDateGROUP BY s.AgentNameHAVING SUM(o.OrderTotal) >= 2000 D、SELECT s.AgentName,SUM(ISNULL(o.OrderTotal,0.00))AS SumOrderTotal FROM SalesAgent s JOIN OrderHeader o ON s.AgentID=o.AgentIDWHERE o.ordertotal =2000 AND o.OrderDate BETWEEN @FromDate AND @ToDate GROUP BY s.AgentName HAVING  SUM(o.OrderTotal)>= 2000