Community Member Profile

Recent Blog Comments By Jaden

• Selecting Top X From Each Group

  Posted on Feb 20, 2011 at 5:58 PM

  @MCouvi Here are two examples of selecting the top n rows, with rows distributed evenly across the groups. These tables are from the MS AdventureWorksLT sample database. SQL Server 2005+ is required, since it uses a CTE and ROW_NUMBER(). This query selects across 3 groups (Count... read more »

• Selecting Top X From Each Group

  Posted on Jul 17, 2009 at 12:37 PM

  For SQL Server, ROW_NUMBER() allows for a single scan of the table, which should provider better performance on larger tables, especially when filtering non-indexed columns versus a join/insert method. SELECT id, name, hair, score, ranknum FROM ( SELECT id, name, hair, sc... read more »