### Introduction

We use many aggregate functions like sum, count, average, min, and max. In LINQ we can use this function in the following manner:-

### Sum

If we want to perform sum aggregate function then we will implement the following queries:-

### Sum with array

``` int[] marks = new int[] { 23, 45, 78, 90, 56, 89, 10, 32 }; //simple sum without condition int res = marks.Sum(); //sum with condition int res_with_where = marks.Where(cond => cond > 50).Sum(); Response.Write("Sum without condition= " + res + "<br/>"); Response.Write("Sum with condition="+ res_with_where+"<br/>"); ```

The output of this code as follows:-

``` Figure 1 ```

### Sum with Generics

``` List<data> dt = new List<data>() { new data{roll_no=1, student="isha", per=100}, new data{roll_no=2, student="neha", per=89}, new data{roll_no=3, student="rahul", per=34} }; int per_sum = dt.Sum(x => x.per); int per_sum_with_conditon = dt.Where(stu => stu.student.EndsWith("ha")).Sum(x => x.per); Response.Write("Sum without condition= " + per_sum + "<br/>"); Response.Write("Sum with condition=" + per_sum_with_conditon + "<br/>"); ```

The output of this code is as follows:-

``` Figure 2 ```

### Sum with database

``` DataContext dc = new DataContext("Data Source=.;Initial Catalog=TechAltum;Integrated Security=True"); //sum without condition int sum_without_cond = dc.GetTable<Class1>().Sum(prod_sum => prod_sum.no_of_prod); //sum with conditon int sum_with_cond = dc.GetTable<Class1>().Where(cond => cond.prod_year == 2001).Sum(prod_sum => prod_sum.no_of_prod); Response.Write("Sum without conditon=" + sum_without_cond + "<br/>"); Response.Write("Sum with conditon=" + sum_with_cond + "<br/>"); ```
``` Figure 3 ```

Similarly we can perform max, min, average and count using LINQ.