Execute the following SQL Server T-SQL script in Management Studio Query Editor to find the missing sequence ranges in SalesOrderID which is an identity sequence Primary Key.

-- SQL missing ranges - SQL misssing records - SQL missing rows - sequence missing values

-- SQL gaps - data gaps - range gaps - SQL select into sql server

USE AdventureWorks;

USE tempdb;

SELECT * INTO SOH

FROM AdventureWorks.Sales.SalesOrderHeader

GO

DELETE SOH WHERE MONTH(OrderDate) = 11

GO

SELECT   MissingRangeStart,

         MissingRangeEnd

FROM     (SELECT soh1.SalesOrderID + 1 AS MissingRangeStart,

                 (SELECT min(SalesOrderID) - 1

                  FROM   SOH AS soh

                  WHERE  soh.SalesOrderID > soh1.SalesOrderID) AS MissingRangeEnd

          FROM   SOH AS soh1

                 LEFT OUTER JOIN SOH AS soh2

                   ON soh1.SalesOrderID = soh2.SalesOrderID - 1

          WHERE  soh2.SalesOrderID IS NULL) AS a

WHERE    MissingRangeEnd IS NOT NULL

ORDER BY MissingRangeStart;

GO

/* Results

MissingRangeStart MissingRangeEnd

44481             44739

47960             48285

57012             58900

*/