How to Calculate the Sum of Values Grouped by Categories using SQL's GROUP BY?

SQL Group by SUM: Calculate Sum of Values Grouped by Categories

In relational database management systems (RDBMS) like MySQL, it's often necessary to aggregate data and compute summary statistics. A common task is to calculate the total of a particular column, grouped by a specific category. This can be achieved using the SQL GROUP BY clause.

Suppose you have a table named category with columns cat_name and amount. Each row represents a category and the corresponding amount associated with it. The goal is to determine the total amount for each unique cat_name.

To solve this problem using MySQL, we can employ the following query:

SELECT cat_name, SUM(amount) AS total_amount
FROM category
GROUP BY cat_name;

This query starts by selecting the cat_name as the first column, which represents the unique category names. It then calculates the sum of the amount column for each unique cat_name and assigns the result to the column total_amount. The GROUP BY clause is used to group the rows by cat_name, ensuring that the total is calculated separately for each distinct category.

Executing this query will return a result set with the category names and their corresponding total amounts, allowing you to analyze the distribution of values across different categories.

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