SQL Server - Equality & NULLs, Sql Server

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-- Create Dataset
--------------------------------------------------------------------------------
CREATE TABLE [value_list]
(
    [ID]     INT NOT NULL PRIMARY KEY,
    [val_1]  INT NULL,
    [val_2]  INT NULL
);

INSERT
  INTO [value_list]
      ([ID], [val_1], [val_2])
VALUES(   1,       1,       1),
      (   2,       2,       2),
      (   3,       3,    NULL),
      (   4,    NULL,    NULL),
      (   5,    NULL,       5),
      (   6,       6,       7)
;

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-- View Data
--------------------------------------------------------------------------------
SELECT [ID],
       [val_1],
       [val_2]
  FROM [value_list]
;

--------------------------------------------------------------------------------
-- Equality Check
--------------------------------------------------------------------------------
SELECT [ID],
       [val_1],
       [val_2]
  FROM [value_list]
 WHERE [val_1] = [val_2]
;

SELECT [ID],
       [val_1],
       [val_2]
  FROM [value_list]
 WHERE [val_1] <> [val_2]
;

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-- Solution using COALESCE
--------------------------------------------------------------------------------
SELECT [ID],
       [val_1],
       [val_2]
  FROM [value_list]
 WHERE COALESCE([val_1], -1) <> COALESCE([val_2], -1)
;

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-- NON Datatype speciffic solution
--------------------------------------------------------------------------------
SELECT [ID],
       [val_1],
       [val_2]
  FROM [value_list]
 WHERE(   [val_1] <> [val_2]
       OR([val_1] IS     NULL AND [val_2] IS NOT NULL)
       OR([val_1] IS NOT NULL AND [val_2] IS     NULL)
      )
;

View schema
Execution time: 0,03 sec, rows selected: 15, rows affected: 6, absolute service time: 0,2 sec