如何使用row_number创建一个在两条记录之间的差异上返回true或false的新字段

Question

I have a railroad crossing database table that has columns CrossingID , ReasonID , and LastUpdated on top of a lot of additional columns.

Each CrossingID has several records going back through time for each time the database was updating that crossing. I want to take the latest two records per CrossingID , order them by LastUpdated , and create a new field that spots any differences between the other fields and returns a true or false.

I figured out how to do the groupings with row_number and using a with statement as I just do not know how to create the checking field for any differences. Here is what I got so far:

WITH CTE AS
(
    SELECT
        ROW_NUMBER() OVER (PARTITION BY crossingid ORDER BY lastupdated DESC) AS RowNo, 
        crossingid, lastupdated, reportstatus, reasonid
    FROM
        statecrossingdata_5year
)
SELECT
    crossingid, lastupdated, rowno, reportstatus, reasonid
FROM
    cte 
WHERE
    rowno <= 2 
ORDER BY 
    crossingid, rowno

The Railroad database is public records and can be found here: https://safetydata.fra.dot.gov/OfficeofSafety/publicsite/DownloadCrossingInventoryData.aspx

Answer 1

Something along these lines

WITH CTE AS
(
    SELECT
        ROW_NUMBER() OVER (PARTITION BY crossingid ORDER BY lastupdated DESC) AS RowNo, 
        crossingid, lastupdated, reportstatus, reasonid
    FROM
        statecrossingdata_5year
),
CTE2 as
(
SELECT
    crossingid, lastupdated, rowno, reportstatus, reasonid
FROM
    cte 
WHERE
    rowno <= 2 
)

SELECT x.*,
CASE WHEN x.reasonID = y.reasonID THEN 'TRUE' ELSE 'FALSE' END
FROM CTE2 x
INNER JOIN CTE2 y
ON x.crossingID = y.crossingID
WHERE X.rowno = 2 AND y.rowno = 1