Функция Sum используется для суммирования данных в массиве / таблице / последовательностях. Примеры:

Python:

sum_of_items = sum([1, 2, 3, 4, 5, 6])
# sum_of_items will be equal to 21

SQL

SELECT SUM(column1) FROM MyTable
WHERE column1 = "condition"

C#,.NET 3.5, LINQ

List<int> array = new List<int>() {1, 2, 3, 4, 5};
int sum = array.Sum();  # sum == 21

Ява

int result = 3 + 7;
//result will be 10

р

x <- c(1.1, 2.5, -0.4)
y <- c(NA, 1.7)
sum(x)
sum(y)
sum(y, na.rm = TRUE)
sum(x, y)  ## as same as sum(c(x, y))
sum(x, y, na.rm = TRUE)  ## as same as sum(c(x, y), na.rm = TRUE)