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  1. Prepare
  2. SQL
  3. Advanced Select
  4. Binary Tree Nodes
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Binary Tree Nodes

  • ssmith1975_soc
     + 0 comments

    An alternative solution

    Using CTE and OUTER APPLY...

    WITH Parents AS (
    SELECT DISTINCT P 
        FROM BST
)

SELECT b.N
    , CASE 
        WHEN b.P IS NULL THEN 'Root'
        WHEN oa.P IS NULL THEN 'Leaf'
        ELSE
        'Inner'       
    END   
    FROM BST b
    OUTER APPLY (
        SELECT b2.P
            FROM Parents b2 
            WHERE b.N = b2.P      
    ) oa
    ORDER BY b.N
;

go

    x