SQL Server 2019

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CREATE TABLE StkTrans (
        TransID INT, 
        Part VARCHAR(25), 
        IN_Nr INT, 
        OUT_Nr INT, 
        OrderNr INT, 
        Type    VARCHAR(3)
    )

    INSERT INTO StkTrans
    (TransID, Part, IN_Nr, OUT_Nr, OrderNr, Type)
    VALUES
    (1, '123-1', 176573, NULL, 666000, 'IN' ),
    (2, '123-1', 176573, 171516, 111222, 'OUT' ),
    (3, '123-1', 179409, NULL, 111222, 'IN' ),
    (4, '123-1', 179409, 198306, 123332, 'OUT' ),
    (5, '123-1', 203944, NULL, 123332, 'IN' ),
    (6, '123-1', 203944, 224789, 125707, 'OUT' ),
    (7, '123-1', 232753, NULL, 125707, 'IN' ),
    (8, '123-1', 232753, 232233, 888777, 'OUT' )
8 rows affected

WITH rCTE AS(
    SELECT *,
           1 AS Iteration
    FROM dbo.StkTrans ST
    WHERE ST.IN_Nr = '232753'
      AND ST.[Type] = 'IN'
    UNION ALL
    SELECT STi.*,
           r.Iteration + 1
    FROM dbo.StkTrans STo
         JOIN dbo.StkTrans STi ON STo.IN_Nr = STi.IN_Nr                     
         JOIN rCTE r ON STo.OrderNr = r.OrderNr
    WHERE STo.[Type] = 'Out'
      AND STi.[Type] = 'In')
SELECT TOP (1) TransID
FROM rCTe
ORDER BY ROW_NUMBER() OVER (ORDER BY Iteration DESC);


TransID


1


DROP TABLE dbo.StkTrans;