UNION Query to update Table
<p>This is my UNION Query</p>

<pre><code>INSERT INTO Master (Player, Won, Lost)
SELECT Player, Sum(Won), Sum(Lost) FROM (
    SELECT First([Master Data Results 2013 - 2016].[Winner]) AS Player,
    Count([Master Data Results 2013 - 2016].[Winner]) AS Won,
    0 AS Lost
    FROM [Master Data Results 2013 - 2016]
    GROUP BY [Master Data Results 2013 - 2016].[Winner]
    HAVING (((Count([Master Data Results 2013 - 2016].[Winner])) &gt; 1))

    UNION

    SELECT First([Master Data Results 2013 - 2016].[Loser]) AS Player,
    0 as Won,
    Count([Master Data Results 2013 - 2016].[Loser]) AS Lost
    FROM [Master Data Results 2013 - 2016]
    GROUP BY [Master Data Results 2013 - 2016].[Loser]
    HAVING (((Count([Master Data Results 2013 - 2016].[Loser])) &gt; 1))
)
GROUP BY Player
</code></pre>

<p>This query does everything that I want, except of course 1 thing.
When the records in my MASTER DATA RESULTS 2013 -2016 is updated with new records and I run my query as here above my MASTER table is all screwed up.
Instead of updating the table the query just adds again all the players with the new numbers.</p>

<p>How can I make sure that the query isn't adding lines to the MASTER table but just update the Won and Lost fields in the MASTER table?</p>

<p>I've played around with unique values and UPDATE but without succes</p>