SQL Server 2022

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CREATE TABLE Products (
    Product VARCHAR(50),
    "Product Key" INT
);
INSERT INTO Products (Product, "Product Key")
VALUES
    ('First', 1),
    ('First', 1),
    ('Second', 1),
    ('Second', 2),
    ('Third', 3),
    ('Four', 3),
    ('Test', 5),
    ('Test', 5);
8 rows affected

SELECT Product
FROM Products
WHERE "Product Key" IN (
    SELECT "Product Key"
    FROM Products
    GROUP BY "Product Key"
    HAVING COUNT(DISTINCT Product) > 1
)
GROUP BY Product;


Product


First

Four

Second

Third