SQL: How to group by with two tables?

I have the tables products and history and I need to group by name:

products = (id_product, name)

history = (id_history, id_product, amount)

I tried this SQL query but it isn’t grouped by name:

SELECT
      products.name,
      sum(history.amount)
FROM history
INNER JOIN products ON history.id_product = products.id_product
GROUP BY
      products.name,
      history.amount,
      history.id_history;

This is the result:

Answer

You should only be grouping by the attributes you need to be aggregated. In this case, you need only products.name.

SELECT
      products.name,
      sum(history.amount) AS [Amount]
FROM history
INNER JOIN products ON history.id_product = products.id_product
GROUP BY
      products.name;

If you need to include products without history (assuming sum should be 0 instead of null in this case), then you can use an OUTER JOIN instead of INNER JOIN to include all products:

SELECT
      products.name,
      COALESCE(sum(history.amount), 0) AS [Amount]
FROM history
    RIGHT OUTER JOIN products ON history.id_product = products.id_product
GROUP BY
      products.name;