Question

I have a query that I always want to return 10 records for:

set rowcount 10
select row_number() over(order by count(*) desc) row_num
    ,hist_report_id
    ,max(rpt_report_name) report_name
from utility.dbo.tbl_report_history
join utility.dbo.tbl_report_definitions
    on hist_report_id = rpt_report_id
where hist_user_id = 1038
group by hist_report_id

Which works fine if I have 10 or more records. The problem is when there are less than 10 records, I still need to return the rownumber field with nulls in the report_id and report_name fields.

If there were only 7 records returned, the results should look like:

row_num report_id report_name
1       id1       name1
2       id2       name2
3       id3       name3
4       id4       name4
5       id5       name5
6       id6       name6
7       id7       name7
8       null      null
9       null      null
10      null      null

Any suggestions?

I am using SQL Server 2008

Answer 1

count() can never return less than zero… so just append 10 dummy rows with -1 in the count column via union

Also, don’t use SET ROWCOUNT because it affects intermediate results

SELECT TOP 10
   row_number() over(order by TheCount desc) AS row_num,
   hist_report_id,
   report_name
FROM
    (
    select 
        ,count(*) AS TheCount
        ,hist_report_id
        ,max(rpt_report_name) AS report_name
    from 
       utility.dbo.tbl_report_history
       join 
       utility.dbo.tbl_report_definitions on hist_report_id = rpt_report_id
    where hist_user_id = 1038
    group by hist_report_id
    UNION ALL
    SELECT TOP 10
         -1, NULL, NULL
    FROM sys.columns
    ) T