Web Listing 3: Code Producing Graphical Depiction of a Random Solution
WITH Nums(n) AS
(
            SELECT 1
  UNION ALL SELECT 2
  UNION ALL SELECT 3
  UNION ALL SELECT 4
  UNION ALL SELECT 5
  UNION ALL SELECT 6
  UNION ALL SELECT 7
  UNION ALL SELECT 8
),
Strings(string, strlen) AS
(
  SELECT CAST(n AS VARCHAR(8)), 1
  FROM Nums

  UNION ALL

  SELECT 
    CAST(PRV.string + CAST(NXT.n AS VARCHAR(1)) AS VARCHAR(8)),
    PRV.strlen + 1
  FROM Strings AS PRV
    JOIN Nums AS NXT
      ON PRV.strlen < 8
      AND PRV.string NOT LIKE '%' + CAST(NXT.N AS VARCHAR(1)) + '%'
      AND NOT EXISTS
        (SELECT * 
         FROM Nums AS D
         WHERE D.n <= PRV.strlen
           AND PRV.strlen + 1 - D.n =
             ABS(NXT.n - CAST(SUBSTRING(PRV.string, D.n, 1) AS INT)))
),
Solutions AS
(
  SELECT string
  FROM Strings
  WHERE strlen = 8
),
RandomSolution AS
(
  SELECT TOP (1) string
  FROM Solutions
  ORDER BY CHECKSUM(NEWID())
),
UnpivotedString AS
(
  SELECT 
    CAST(SUBSTRING(string, C.n, 1) AS INT) AS row,
    C.n AS col
  FROM RandomSolution
    JOIN Nums AS C
      ON C.n <= 8
)
SELECT row,
  [1] AS a, [2] AS b, [3] AS c, [4] AS d,
  [5] AS e, [6] AS f, [7] AS g, [8] AS h
FROM UnpivotedString
  PIVOT(COUNT(col) FOR col IN([1],[2],[3],[4],[5],[6],[7],[8])) AS P
ORDER BY row;