How Can I Find the Most Frequent Value in an SQL Column for Each Category?

Finding the Most Common Values in an SQL Column

Determining the most prevalent value for each value in a separate column is a common requirement in data analysis. When working with tables where columns store categorical data, such as countries and food items, it's often useful to find the most frequently consumed food for each country.

One approach involves creating temporary tables to count occurrences and identify maximum counts. However, PostgreSQL 9.4 introduced a more straightforward solution:

Using the mode() Function

The mode() function calculates the most commonly occurring value in a set of ordered data. By incorporating it into a query, we can efficiently find the most common food item for each country:

select mode() within group (order by food_id)
from munch
group by country

This query returns a table with the country as one column and the mode value as another:

country | mode
--------------
GB      | 3
US      | 1

Where '3' represents the food item that was consumed most frequently in Great Britain (GB), and '1' corresponds to the most common food item in the United States (US). This approach provides a concise and efficient solution for extracting the most common values for each category.

The above is the detailed content of How Can I Find the Most Frequent Value in an SQL Column for Each Category?. For more information, please follow other related articles on the PHP Chinese website!