Top 1 with a left join
问题 Given the query below there might be multiple rows in dps_markers with the same marker key but we only want to join against the first. If I take this query and remove the top 1 and ORDER BY I get a value for mbg.marker_value but run as it is it always returns null SELECT u.id, mbg.marker_value FROM dps_user u LEFT JOIN (SELECT TOP 1 m.marker_value, um.profile_id FROM dps_usr_markers um (NOLOCK) INNER JOIN dps_markers m (NOLOCK) ON m.marker_id= um.marker_id AND m.marker_key =