Explanation on the usage of sum in sql

The SUM function in SQL is used to calculate the sum of a set of values, and the syntax is SUM(expression). It is often used in conjunction with a WHERE clause to sum values ​​under specific conditions. The SUM function can be used with the DISTINCT keyword to sum unique values, or with the GROUP BY clause to sum grouped data.

SUM function in SQL

The SUM function is a commonly used aggregate function in SQL and is used to calculate a set of values. Sum. It is often used for statistical analysis and data aggregation.

Syntax

<code class="sql">SUM(expression)</code>

Where expression is the column or expression to calculate the sum.

Example

The following query calculates the sum of all order amounts in the customer_orders table:

<code class="sql">SELECT SUM(order_amount)
FROM customer_orders;</code>

Usage

## The #SUM function is often used in conjunction with the WHERE clause to sum values ​​under specific conditions. For example, the following query calculates the sum of all orders with a total order amount greater than $100:

<code class="sql">SELECT SUM(order_amount)
FROM customer_orders
WHERE order_amount > 100;</code>

Note

The SUM function cannot be used to sum NULL values . If NULL values ​​are present, they are ignored.
• The SUM function can be used with the DISTINCT keyword to sum unique values.
• The SUM function can be used with the GROUP BY clause to sum grouped data.

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