"SELECT Fixtures.Fixture_id, Fixtures. [ , MatchReport.Fixture_id FROM Fixtures LEFT JOIN MatchReports On Fixtures.Fixture_id = MatchReports.Fixture_id WHERE date.....etc"
What this does is to return all fixtures, whether there is a match report or not. In the final column of your results ( MatchReport.Fixture_id) you will get the fixture_id for those with match reports, or NULL if there isn't one. Then you would do ... (More)