Question

I have to create a report which has AccountSegment as rows and a 2-week date range as column header. The column values will be a count of the number of records in the table having the associated segment/date range.

So the desired output looks something like this:

AcctSeg  4/9/12-4/20/12   4/23/12-5/4/12   5/7/12-5/18/12
Segment1       100             200              300
Segment2       110             220              330
Segment3       120             230              340

The following query does what I want, but just looks so inefficient and ugly. I was wondering if there is a better way to accomplish the same thing:

SELECT
    AccountSegment = S.Segment_Name,
    '4/9/2012 - 4/20/2012' = SUM(CASE WHEN date_start BETWEEN '2012-04-09' AND '2012-04-20' THEN 1 END),
    '4/23/2012 - 5/4/2012' = SUM(CASE WHEN date_start BETWEEN '2012-04-23' AND '2012-05-04' THEN 1 END),
    '5/7/2012 - 5/18/2012' = SUM(CASE WHEN date_start BETWEEN '2012-05-07' AND '2012-05-18' THEN 1 END),
    '5/21/2012 - 6/1/2012' = SUM(CASE WHEN date_start BETWEEN '2012-05-21' AND '2012-06-01' THEN 1 END),
    '6/4/2012 - 6/15/2012' = SUM(CASE WHEN date_start BETWEEN '2012-06-04' AND '2012-06-15' THEN 1 END),
    '6/18/2012 - 6/29/2012' = SUM(CASE WHEN date_start BETWEEN '2012-06-18' AND '2012-06-29' THEN 1 END),
    '7/2/2012 - 7/13/2012' = SUM(CASE WHEN date_start BETWEEN '2012-07-02' AND '2012-07-13' THEN 1 END),
    '7/16/2012 - 7/27/2012' = SUM(CASE WHEN date_start BETWEEN '2012-07-16' AND '2012-07-27' THEN 1 END),
    '7/30/2012 - 8/10/2012' = SUM(CASE WHEN date_start BETWEEN '2012-07-30' AND '2012-08-10' THEN 1 END)
FROM
    dbo.calls C
    JOIN dbo.accounts a ON C.parent_id = a.id
    JOIN dbo.accounts_cstm a2 ON a2.id_c = A.id
    JOIN dbo.Segmentation S ON a2.[2012_segmentation_c] = S.Segment_Num
WHERE
    c.deleted = 0 
GROUP BY
    S.Segment_Name
ORDER BY
    MIN(S.Sort_Order)

Answer 1

It looks fine, but I would suggest one performance improvement:

where c.deleted = 0 and
      date_start between  '2012-04-09' AND '2012-08-10'

This will limit the aggregation only to rows you need . . . unless you want everything listed with empty data.

I would be inclined to add else 0 to the case statements, so 0s appear instead of NULLs.