หาค่า max ค่ะ SELECT a.CustomerCode as Customer,b.Itemcode as Item, sum(b.qtyorder) AS total_qty FROM

// ****************** ใน View ******************
SELECT QR_FIRST.*
   ,row_number() 
      OVER (ORDER BY QR_FIRST.Item_code 
         ,QR_FIRST.total ,QR_FIRST.customer_code) AS dynamic_id
FROM 
(
   SELECT a.CustomerCode as customer_code 
      ,b.Itemcode as Item_code, sum(b.qtyorder) AS total 
   FROM SO a INNER JOIN SO_Detail b 
      ON a.SOID = b.SOID
   GROUP BY  b.Itemcode ,a.CustomerCode
) AS QR_FIRST
ORDER BY QR_FIRST.Item_code ,QR_FIRST.total ,QR_FIRST.customer_code

// ***********************************
View นี้ให้ชื่อว่า ViewGetMaxItem ค่ะ
และที่ Command จะเขียนดังนี้ ( ไม่ต้องการ Field ไหนก็ลบออกนะคะ )

SELECT 
    CASE 
       WHEN QR_MAX.first_rec_id = QR_CUSTOMER.dynamic_id
          THEN CONVERT(VARCHAR(50) ,QR_MAX.item_code)
       ELSE ''
    END AS item_code_label
   ,QR_CUSTOMER.item_code,QR_CUSTOMER.CUSTOMER_CODE as custmain 
   ,QR_MAX.max_item ,QR_MAX.total_customer
   ,CASE 
       WHEN QR_MAX.first_rec_id = QR_CUSTOMER.dynamic_id
          THEN QR_MAX.max_item
       ELSE 0
    END AS filter_max_item     
   ,CASE 
       WHEN QR_MAX.first_rec_id = QR_CUSTOMER.dynamic_id
          THEN QR_MAX.total_customer
       ELSE 0
    END AS filter_total_customer
   ,CASE 
       WHEN QR_MAX.first_rec_id = QR_CUSTOMER.dynamic_id
          THEN ''
       ELSE 'Not include by same maximum order'
    END AS comment
FROM dbo.ViewGetMaxItem AS QR_CUSTOMER 
   RIGHT JOIN 
   (
      SELECT QR_INNER.item_code, MAX(QR_INNER.total) AS max_item 
         ,COUNT(QR_INNER.customer_code) AS total_customer 
         ,MIN(QR_INNER.dynamic_id) as first_rec_id
      FROM dbo.ViewGetMaxItem AS QR_INNER
      GROUP BY QR_INNER.item_code 	
   ) AS QR_MAX
      ON (QR_CUSTOMER.item_code=QR_MAX.item_code)
         AND (QR_CUSTOMER.total = QR_MAX.max_item)
ORDER BY QR_CUSTOMER.item_code ,QR_CUSTOMER.CUSTOMER_CODE;