How to use sum function in oracle

The SUM function calculates the sum of a series of values ​​in Oracle. Syntax: SUM(expression), where expression is a numeric expression or column name. It can sum all row values ​​in a column, or sum rows that meet a specific condition via a WHERE clause. The SUM function returns a value of type NUMBER and returns a positive number even if the argument is negative. It supports advanced usage, such as with GROUP BY and HAVING clauses, and as a window function.

The SUM function in Oracle

Definition

The SUM function is in Used in Oracle to calculate the sum of a set of values ​​or expressions.

Syntax

<code>SUM(expression)</code>

Where:

• expression: The numeric expression or column name to calculate the sum.

Usage

• #The SUM function sums all row values ​​in a column.
• You can also use the SUM function in the WHERE clause to sum rows that meet specific conditions.
• The return value of the SUM function is the data type NUMBER.

Example

<code>-- 计算所有员工的薪水总和
SELECT SUM(salary) FROM employees;

-- 计算部门 ID 为 10 的所有员工的薪水总和
SELECT SUM(salary) FROM employees WHERE department_id = 10;

-- 计算大于 5000 美元的薪水总和
SELECT SUM(salary) FROM employees WHERE salary > 5000;</code>

Note

• If the parameter of the SUM function is NULL, it will be returned The value is NULL.
• If the parameter of the SUM function is a negative number, the return value is still a positive number.
• The SUM function can be applied to both numbers and strings. If you want to sum strings, the strings must be enclosed in single quotes.

Advanced Usage

In addition to basic usage, the SUM function also supports some advanced usage:

• GROUP BY clause: The SUM function can be used with the GROUP BY clause to sum grouped data.
• HAVING clause: The SUM function can be used with the HAVING clause to sum groupings that meet certain conditions.
• Window function: The SUM function can be used as a window function to calculate the sum of values ​​within the window.

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