我创建了一个查询，但它无法正常工作

WITH rows AS
(
    SELECT   
        *, ROW_NUMBER() OVER (ORDER BY dtDeliveryDate) AS rn
    FROM    
        TCheckRecipient
)
SELECT 
    AVG(avarage) 
FROM
    (SELECT 
         TCheck.iCheckId, 
         AVG(DATEDIFF(minute, mc.dtDeliveryDate, mp.dtDeliveryDate)) AS average
     FROM    
         rows mc
     LEFT JOIN
         TCheck ON TCheck.iCheckId = mc.iCheckId
     JOIN    
         rows mp ON mc.rn = mp.rn - 1
     GROUP BY 
         TCheck.iCheckId)
WITH rows AS
(
    SELECT   
        *, ROW_NUM