Sql – Select top 10 records for each category

greatest-n-per-groupsqlsql serversql-server-2005

I want to return top 10 records from each section in one query. Can anyone help with how to do it? Section is one of the columns in the table.

Database is SQL Server 2005. I want to return the top 10 by date entered. Sections are business, local, and feature. For one particular date I want only the top (10) business rows (most recent entry), the top (10) local rows, and the top (10) features.

Best Answer

If you are using SQL 2005 you can do something like this...

SELECT rs.Field1,rs.Field2 
    FROM (
        SELECT Field1,Field2, Rank() 
          over (Partition BY Section
                ORDER BY RankCriteria DESC ) AS Rank
        FROM table
        ) rs WHERE Rank <= 10

If your RankCriteria has ties then you may return more than 10 rows and Matt's solution may be better for you.

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Sql – Insert into … values ( SELECT … FROM … )

Try:

INSERT INTO table1 ( column1 )
SELECT  col1
FROM    table2

This is standard ANSI SQL and should work on any DBMS

It definitely works for:

Oracle
MS SQL Server
MySQL
Postgres
SQLite v3
Teradata
DB2
Sybase
Vertica
HSQLDB
H2
AWS RedShift
SAP HANA
Google Spanner

Sql – How to perform an IF…THEN in an SQL SELECT

The CASE statement is the closest to IF in SQL and is supported on all versions of SQL Server.

SELECT CAST(
             CASE
                  WHEN Obsolete = 'N' or InStock = 'Y'
                     THEN 1
                  ELSE 0
             END AS bit) as Saleable, *
FROM Product

You only need to use the CAST operator if you want the result as a Boolean value. If you are happy with an int, this works:

SELECT CASE
            WHEN Obsolete = 'N' or InStock = 'Y'
               THEN 1
               ELSE 0
       END as Saleable, *
FROM Product

CASE statements can be embedded in other CASE statements and even included in aggregates.

SQL Server Denali (SQL Server 2012) adds the IIF statement which is also available in access (pointed out by Martin Smith):

SELECT IIF(Obsolete = 'N' or InStock = 'Y', 1, 0) as Saleable, * FROM Product

Best Answer

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Sql – Insert into … values ( SELECT … FROM … )

Sql – How to perform an IF…THEN in an SQL SELECT

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