LISTING 1: Stored Procedure to Populate the Magic Square

CREATE PROC FillMagicSquare
  @size AS int
AS

DELETE MagicSquare

-- Insert the first number to the middle cell in the first row
INSERT INTO MagicSquare(row, col, value) VALUES(1, @size / 2 + 1, 1)

-- Insert the rest of the numbers while the last number does not exist in the table
WHILE NOT EXISTS (SELECT * FROM MagicSquare WHERE value = @size * @size)

  INSERT INTO MagicSquare(row, col, value)
    
    -- decide which coordinates to use (above / right cell or cell beneath)
    -- based on the NULLs returned from the ROJ
    SELECT
      CASE
        WHEN MS.row IS NULL THEN O1.row
        ELSE O2.row
      END AS row,
      CASE
        WHEN MS.col IS NULL THEN O1.col
        ELSE O2.col
      END AS col,
      O1.value

    FROM

      -- Input 1: base table      
      MagicSquare AS MS

      -- Join 1: existing_cell ROJ above / right cell
      -- NULLs indicate cell is not occupied
      RIGHT OUTER JOIN

      -- Input 2: above / right cell info
      (SELECT
         CASE
           WHEN row - 1 = 0 THEN @size
           ELSE row - 1
         END AS row,
         CASE
           WHEN col + 1 > @size THEN 1
           ELSE col + 1
         END AS col,
         value + 1 AS value
       FROM MagicSquare
       WHERE value = (SELECT MAX(value)
                      FROM MagicSquare)) AS O1
     
      ON MS.row = O1.row AND MS.col = O1.col

      -- Join 2: existing_cell ROJ above / right cell CJ cell beneath
      CROSS JOIN

      -- Input 3: cell beneath info
      (SELECT
         CASE
           WHEN row + 1 > @size THEN 1
           ELSE row + 1
         END AS row,
         col,
         value + 1 AS value
       FROM MagicSquare
       WHERE value = (SELECT MAX(value)
                      FROM MagicSquare)) AS O2
GO