SQL how to remove duplicate results from same table
Following code should work, tested in Memory table:

DECLARE @TBL AS TABLE
(   
    ID INT IDENTITY(1, 1) PRIMARY KEY CLUSTERED,
    First VARCHAR(10),
    Last VARCHAR(10),
    Address VARCHAR(30),
    Quantity INT,
    Price INT,
    Discount VARCHAR(10)
);

INSERT @TBL (First, Last, Address, Quantity, Price, Discount )
    VALUES 
    ('rolp', 'Gaflp', '24 street', 1, 155, '10%'),
    ('rolp', 'Gaflp', '24 street', 3, 202, '5%'),
    ('rolp', 'Gaflp', '24 street', 4, 312, '6%');

WITH CTE AS (
    SELECT *, ROW_NUMBER() OVER (PARTITION BY First, Last, Address ORDER BY Quantity) AS Row
        FROM @TBL
    )
SELECT  ID, 
        CASE WHEN Row = 1 THEN First ELSE '' END AS First,
        CASE WHEN Row = 1 THEN Last ELSE '' END AS Last,
        CASE WHEN Row = 1 THEN Address ELSE '' END AS Address,
        Quantity, Price, Discount
    FROM CTE;