Cara mendapatkan induk umum terendah untuk 2 baris dalam tabel rekursif (SQL)

Beberapa suntingan kecil pada jawaban Quassnoi, dan berhasil:

WITH
    hier1 (id, parent) AS (
    SELECT      id, parent
    FROM        table
    WHERE       id = @user1
    UNION ALL
    SELECT      id, parent
    FROM        table l, hier1 h
    WHERE       l.id = h.parent
    ),
    hier2 (id, parent) AS (
    SELECT      id, parent
    FROM        table
    WHERE       id = @user2
    UNION ALL
    SELECT      id, parent
    FROM        table l, hier1 h
    WHERE       l.id = h.parent
    )
SELECT  TOP 1 hier1.id
FROM    hier1, hier2
WHERE   hier1.id = hier2.id