Use a view to determine if a previous date exists - sql

Question

Currently, I have an orders table that I want to extract information from. There are 4 main fields I am looking for: Order no, customer no, date1, and date 2.
Date 1 is the minimum date in the table for a specific customer number prior to the date associated with the order number within a 12 month period (that's not the order number date).
Date 2 is the minimum date in the table for a specific customer number prior to date1 within a 12 month period (that's not date 1)
Here is what I have so far but it doesn't seem to be pulling in any data. Any help is appreciated!
With CTE as
(SELECT Order_no, customer_no, MIN(order_date) AS date1
FROM dbo.orders
WHERE (order_date >= DATEADD(month, - 12, order_date)
and (order_date < DATEADD(day, - 1, order_date)))
GROUP BY Order_no, customer_no)
Select x.order_no, x.customer_no, min(x.order_date) as date2, cte.date1
from dbo.orders x
LEFT OUTER JOIN CTE ON cte.order_no=x.order_no
where x.order_date > DATEADD(month, - 12, cte.date1)
AND x.order_date < DATEADD(DAY, - 1, cte.date1)
Group by x.order_no, x.customer_no, cte.date1

Answer 1

You need to figure out what is filtering based on the data you have. This is more about data meaning than syntax.
Start by making sure the cte is returning any records. and then make sure by checking the data that they are th records you wanted.
With CTE as
(SELECT Order_no, customer_no, MIN(order_date) AS date1
FROM dbo.orders
WHERE (order_date >= DATEADD(month, - 12, order_date)
and (order_date < DATEADD(day, - 1, order_date)))
GROUP BY Order_no, customer_no)
select * from CTE
Once you are sure of this try with just the join
With CTE as
(SELECT Order_no, customer_no, MIN(order_date) AS date1
FROM dbo.orders
WHERE (order_date >= DATEADD(month, - 12, order_date)
and (order_date < DATEADD(day, - 1, order_date)))
GROUP BY Order_no, customer_no)
Select *
from dbo.orders x
LEFT OUTER JOIN CTE ON cte.order_no=x.order_no
Then add the where criteria back in one at a time. This is the basic technique you use when the query does not havea a syntax issue but is not returning the correct data.
Based on the comments, this is what I would try next:
SELECT Order_no, customer_no,order_date, DATEADD(month, - 12, order_date) as ordermonth, DATEADD(day, - 1, order_date) as orderday
FROM dbo.orders
This will tell you why none of your records meet the criteria.