Limit the number of rows per ID

问题

I am trying to limit the number of rows per case to only 5 rows. Some cases have only 1 or 2 rows but some have 15 or more.

This is an example of a stored procedure that I am using to count the number of rows per case.

SELECT     ROW_NUMBER() OVER(partition by rce.reportruncaseid ORDER BY rce.Reportruncaseid) AS Row, rce.ReportRunCaseId AS CaseId, YEAR(rce.EcoDate) AS EcoYear
FROM         PhdRpt.ReportCaseList AS rcl INNER JOIN
                  PhdRpt.RptCaseEco AS rce ON rce.ReportId = rcl.ReportId AND rce.ReportRunCaseId = rcl.ReportRunCaseId
GROUP BY rce.ReportId, rce.ReportRunCaseId, YEAR(rce.EcoDate)
Order by rce.ReportRunCaseId, YEAR(rce.EcoDate)

Here is a screenshot of what this stored procedure produces: screenshot

I have tried to use the where clause but it will not allow me to place a window function after the where clause. It also does not recognize my "Row" alias.

Is there another way to count the number or rows per case (instead of a window function) so that I can use the where clause? Or is there a way to limit the records per case to 5 using my existing stored procedure?

Thank you in advance for your help.

回答1:

You can wrap your statement in a CTE since SQL Server supports it.

WITH records
AS
(
    SELECT  ROW_NUMBER() OVER(PARTITION BY rce.reportruncaseid 
                              ORDER BY rce.Reportruncaseid) AS Row, 
            rce.ReportRunCaseId AS CaseId, 
            YEAR(rce.EcoDate) AS EcoYear
    FROM    PhdRpt.ReportCaseList AS rcl 
                INNER JOIN PhdRpt.RptCaseEco AS rce 
                    ON  rce.ReportId = rcl.ReportId 
                        AND rce.ReportRunCaseId = rcl.ReportRunCaseId
    GROUP   BY rce.ReportId, rce.ReportRunCaseId, YEAR(rce.EcoDate)
)
SELECT CaseId, EcoYear
FROM   records
WHERE  row <= 10
ORDER  BY CaseId, EcoYear

来源：https://stackoverflow.com/questions/16217612/limit-the-number-of-rows-per-id

标签

sql

sql-server

window-functions