calculate marketshare per speaker

gistfile1.sql

SELECT speaker.provider_id, drx.product_name, drx.rx_year, drx.rx_month, SUM(drx.nrx_cnt) AS rx_ct
FROM provider speaker
     INNER JOIN event_provider speakerevt ON (speakerevt.provider_id = speaker.provider_id)
     INNER JOIN roi_campaign_project rcp ON (rcp.project_id = speaker.project_id)
     INNER JOIN roi_campaign rc ON (rc.roi_campaign_id = rcp.roi_campaign_id)
     INNER JOIN [event] e ON (e.event_id = speakerevt.event_id)
     INNER JOIN event_provider attendeeevt ON (attendeeevt.event_id = e.event_id)
     INNER JOIN provider attendee ON (attendee.provider_id = attendeeevt.provider_id and attendeeevt.provider_id != speaker.provider_id)
     INNER JOIN provider_rx_segment drx ON (drx.provider_id = attendee.provider_id)
WHERE rcp.roi_campaign_id = 46 AND e.event_start_time BETWEEN rc.event_rx_start AND DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,rc.event_rx_end)+1,0))
      AND speakerevt.event_role_id = 2 
      AND attendeeevt.event_role_id = 1
      AND (drx.rx_year = YEAR(DATEADD(MONTH, -1, rc.event_start)) AND drx.rx_month = MONTH(DATEADD(MONTH, -1, rc.event_start))
           OR drx.rx_year = YEAR(rc.event_rx_end) AND drx.rx_month = MONTH(rc.event_rx_end))
GROUP BY speaker.provider_id, drx.product_name, drx.rx_year, drx.rx_month