How Can I Efficiently Find the Most Frequently Consumed Food Per Country in PostgreSQL?

Efficiently Retrieving Frequently Occurring Values in SQL

Consider a database table containing data on countries, food items, and mealtime consumption. To determine the most frequently consumed food for each country, one might envision a multi-step approach as outlined in the reference query. However, modern database systems offer more concise and optimized solutions.

PostgreSQL Optimization with mode() Function

PostgreSQL version 9.4 introduced the mode() aggregate function, which significantly simplifies the task of identifying the most common values within grouped data. The following query demonstrates its usage:

SELECT mode() WITHIN GROUP (ORDER BY food_id)
FROM munch
GROUP BY country

This query produces a table with two columns: country and mode, where the latter represents the most frequent food_id for each country. The ORDER BY clause ensures that ties are broken in favor of the smallest food_id.

Additional Resources and Enhancements

• For further documentation on the mode() function, refer to the PostgreSQL wiki: https://wiki.postgresql.org/wiki/Aggregate_Mode
• For general information on aggregate functions in PostgreSQL, visit: https://www.postgresql.org/docs/current/static/functions-aggregate.html#FUNCTIONS-ORDEREDSET-TABLE

The above is the detailed content of How Can I Efficiently Find the Most Frequently Consumed Food Per Country in PostgreSQL?. For more information, please follow other related articles on the PHP Chinese website!