Question

I have a query which returns analytics style information about a job board and where applicants are coming from in the following structure:

The query to access that is:

SELECT   g.name AS [Source]
        ,SUM(CASE WHEN v.cost = 0 THEN 1 ELSE 0 END) AS [Organic Clicks]
        ,SUM(CASE WHEN v.cost <> 0 THEN 1 ELSE 0 END) AS [Paid Clicks]
        ,COUNT(v.id) AS [Total Clicks]
        ,SUM(CASE WHEN a.applicant = 1 AND v.cost = 0 THEN 1 ELSE 0 END) AS [Organic Applicants]
        ,SUM(CASE WHEN a.applicant = 1 AND v.cost <> 0 THEN 1 ELSE 0 END) AS [Paid Applicants]
        ,SUM(CASE WHEN a.applicant = 1 THEN 1 ELSE 0 END) AS [Total Applicants]
        ,SUM(v.cost/100.0) AS [Spend]
FROM a_views v
LEFT OUTER JOIN a_views a
    ON v.viewerid = a.viewerid
    AND v.sessionsourceid = a.sessionsourceid
    AND a.applicant = 1
JOIN a_sources s
    ON v.sourceid = s.id
JOIN a_sourcegroups g ON s.fk_sourcegroup = g.id
--JOIN jobs j ON v.jobid = j.anal_id AND j.featured = 1
WHERE v.hostName = @jobboard
    AND v.viewed_at >= @start AND v.viewed_at <= @end
GROUP BY g.name

The only issue is that in the LEFT OUTER JOIN a_views block there may be multiple records returned. What I need to do is only have the record tracked once in the Click sums but each time it’s found for the Applicant sums.

I did find a similar question of this happening on this question, but the answerer didn’t actually give much information.

To resum what I need, each instance of the record in the right side of the join, but only 1 instance of the record on the left side.

Answer 1

One way you could do this without changing your query entirely is separate the Click sums and Applicant sums into two separate queries, UNION them together and then group/sum them again.

Something like this (pseudo code):

SELECT
        Source
        ,SUM([Organic Clicks])
        ,.....
FROM
(
SELECT   g.name AS [Source]
        ,SUM(CASE WHEN v.cost = 0 THEN 1 ELSE 0 END) AS [Organic Clicks]
        ,SUM(CASE WHEN v.cost <> 0 THEN 1 ELSE 0 END) AS [Paid Clicks]
        ,COUNT(v.id) AS [Total Clicks]
        ,0 AS [Organic Applicants]
        ,0 AS [Paid Applicants]
        ,0 AS [Total Applicants]
        ,SUM(v.cost/100.0) AS [Spend]
FROM
        ClickOnlyTables

UNION ALL

SELECT   g.name AS [Source]
        ,0 AS [Organic Clicks]
        ,0 AS [Paid Clicks]
        ,0 AS [Total Clicks]
        ,SUM(CASE WHEN a.applicant = 1 AND v.cost = 0 THEN 1 ELSE 0 END) AS [Organic Applicants]
        ,SUM(CASE WHEN a.applicant = 1 AND v.cost <> 0 THEN 1 ELSE 0 END) AS [Paid Applicants]
        ,SUM(CASE WHEN a.applicant = 1 THEN 1 ELSE 0 END) AS [Total Applicants]
        ,0 AS [Spend]
FROM
        ApplicantTables
)
GROUP BY
        Source