t-SQL to find Top 10 Records for Each Group

row-number, sql, subquery, t-sql

Solution

I think you're looking for `ROW_NUMBER()` with a `PARTITION BY`

SELECT * 
FROM (
    SELECT 
        ROW_NUMBER() OVER(PARTITION BY t.TranSID ORDER BY t.TranSID, SUM(IIF(TranTypeID = 'CO', td.Qty * CAST(td.Price AS money) * - 1, td.Qty * CAST(td.Price AS money))) DESC) as RowNum,            
        a.ABID, 
        a.ABName, 
        t.TranSID, 
        SUM(IIF(TranTypeID = 'CO', td.Qty * CAST(td.Price AS money) * - 1, td.Qty * CAST(td.Price AS money))) AS TotalSales
    FROM Trans t 
       INNER JOIN TransDetail td 
           ON t.TranID = td.TranID 
       INNER JOIN ABook a 
           ON t.TranABID = a.ABID
    WHERE (t.TranDate BETWEEN CONVERT(DATETIME, '2012-01-01 00:00:00', 102) AND CONVERT(DATETIME, '2013-01-01 00:00:00', 102)) 
       AND t.TranTypeID in ('SO','CA','CO')
       AND (t.TranStatus <> 'V')
    GROUP BY a.ABID, a.ABName, t.TranSID
    HAVING  (NOT (a.ABName LIKE '%cash%'))
) a
WHERE a.RowNum <=10

This will assign a row number to each record in the grouping (the column defined by the `PARTITION`, going from 1 to n. From there, you can run a `SELECT` on it to grab any number of records per group.

Problem

Original source