How to calculate the Manhattan Distance with SQL function / procedure

Does anybody have a simple function / store procedure on how to calcula开发者_如何学运维te the Manhattan Distance when given two XY coordinate pairs?

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It's just the sum of the difference between coordinate pairs:

|x2 - x1| + |y2 - y1|

This hardly warrants a stored procedure.

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How about

CREATE OR REPLACE FUNCTION MANHATTAN_DISTANCE(X1 NUMBER,
                                              Y1 NUMBER,
                                              X2 NUMBER,
                                              Y2 NUMBER)
  RETURN NUMBER IS
BEGIN
  RETURN ABS(X1 - X2) + ABS(Y1 - Y2);
END MANHATTAN_DISTANCE;

Share and enjoy.

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This is easy. The Manhattan Distance is just the sum of the distances in each dimension, so:

SELECT ABS(x2 - x1) + ABS(y2 - y1) AS manhattan_distance FROM your_table