What does sum mean in sql?

The meaning of SUM in SQL is to calculate the sum of a set of values, and the syntax is SUM(expression). It can be applied to numeric columns, ignoring NULL values, and can be used with the GROUP BY clause to calculate the sum of values ​​in a specific group.

The meaning of SUM in SQL

SUM is an aggregate function in SQL, used to calculate the sum of a set of values. and. Its syntax is as follows:

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

where expression is the numeric expression or column whose sum is to be calculated.

Usage

The SUM function can be applied to a numeric column to obtain the sum of all values ​​in the column. For example:

<code class="sql">SELECT SUM(salary) FROM employees;</code>

This will return the sum of all values ​​in the salary column in the employees table.

Note

• The SUM function ignores NULL values.
• If expression is a text or date type, the SUM function returns NULL.
• The SUM function can be used with the GROUP BY clause to calculate the sum of values ​​in a specific group.

Example

The following example demonstrates how to use the SUM function to calculate the total sales of different departments:

<code class="sql">SELECT department, SUM(sales) AS total_sales
FROM sales
GROUP BY department;</code>

This will return a result set , where each row shows a department and its total sales.

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