SELECT
	SUM(revenue) AS "Revenue",
    SUM(transactions)/SUM(visits) AS "Conversion"
FROM
	[dbo].[EmailTraffic]
GROUP BY
	[dbo].[EmailTraffic].CAMPAIGN_ID

	SELECT
			COUNT(DISTINCT [dbo].[EmailTraffic].USERID)/COUNT(DISTINCT [dbo].[SENT].USERID)
		FROM
			[dbo].[SENT]
		INNER JOIN
			[dbo].[OPEN]
		ON
			[dbo].[OPEN].USERID = [dbo].[SENT].USERID
		INNER JOIN
			[dbo].[EmailTraffic]
		ON
			[dbo].[OPEN].USERID = [dbo].[EmailTraffic].USERID

GROUP BY
	[dbo].[EmailTraffic].CAMPAIGN_ID