I thought I had a simple run of the mill problem, but I can't manage to figure out how to slice it. Assume I have a table of Deliveries that has the OrderNumber, the DeliveryNumber and the DeliveryDate. The question I want to ask is "Which OrderNumbers have DeliverDates that all aren't in the same week"

Here is a test script.

DECLARE @DeliveryTable Table
    OrderNumber INT,
    DeliveryNumber INT,
    DeliveryDate Date

INSERT INTO @DeliveryTable 
(OrderNumber, DeliveryNumber, DeliveryDate)
(1,300, '2020-04-27'),
(1,301, '2020-04-28'),
(1,302, '2020-04-30'),
(4,730, '2020-04-26'),
(4,731, '2020-04-28'),
(4,732, '2020-05-05')

My query would return OrderNumber={4} because the '2020-05-05' is not in the same week as '2020-04-28' and '2020-04-26'. OrderNumber 1 would not be returned because all the deliveries are in the same week.

I've thought about using a LEAD/LAG function, but there can be an arbitrary number of Deliveries so I wouldn't know how far to LEAD/LAG. I was thinking about using some type of join, but I don't know what I would join on other than ( ..DATEPART(WK, first.DeliveryDate) <> DATEPART(WK, second.DeliveryDate)..) but that seems hamfisted to do over 1.4 million rows.

  • Do you mean same week number or calendar week? For example if you add to your list (5,733, '2020-12-31'), (5,733, '2020-01-01') then what would you expect? Should those be the same week?
    – BCM
    Apr 30, 2020 at 16:03

2 Answers 2


Try following query

SELECT OrderNumber
FROM @DeliveryTable
GROUP BY OrderNumber
HAVING DATEPART(WEEK, MIN(DeliveryDate)) < DATEPART(WEEK, max(DeliveryDate))

Calculating date-diff can lead to incorrect results because if we compare difference of Sunday and next Monday it will return 1, but these days are in different weeks.

  • It's worth noting that this would incorrectly report when DeliveryDate is 1 year apart. Probably not a concern, but should be noted.
    – Graham
    May 30, 2020 at 21:29

Here is an alternative to the answer by Artashes Khachtryan which would support delivery dates a year apart. If that is not a concern, it provides no other benefit:

SELECT OrderNumber 
FROM @DeliveryTable
GROUP BY OrderNumber
HAVING COUNT(DISTINCT DATEADD(D, -DATEPART(Weekday, DeliveryDate), DeliveryDate)) > 1 

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