GroupBy in Linq

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GroupBy in Linq

Tuhin Paul · Answer

GroupBy in LINQ is used to group records that have the same value in a particular column or property. Simple Example Suppose you have a list of employees: var employees = new List { new Employee { Name = "John", Department = "IT" }, new Employee { Name = "Mary", Department = "HR" }, new Employee { Name = "David", Department = "IT" }, new Employee { Name = "Sara", Department = "HR" } }; Group By Department var groupedEmployees = employees.GroupBy(e => e.Department); Reading the Result foreach (var group in groupedEmployees) { Console.WriteLine($"Department: {group.Key}"); foreach (var employee in group) { Console.WriteLine(employee.Name); } }

Pankajkumar Patel · Answer

Hi Yaad Dhakal, GroupBy in LINQ is used to group elements that share a key. Syntax var grouped = items.GroupBy(x => x.KeyProperty); It returns groups of type IGrouping . Example var students = new[] { new { Name = "A", Grade = "A" }, new { Name = "B", Grade = "B" }, new { Name = "C", Grade = "A" } }; var byGrade = students.GroupBy(s => s.Grade); foreach (var group in byGrade) { Console.WriteLine($"Grade: {group.Key}"); foreach (var student in group) Console.WriteLine($" {student.Name}"); } Glad to help! Please mark this answer as the accepted answer if it helped you out!

Cynthia Sathuragiri · Answer

GroupBy in LINQ is used to group a collection of items based on a key. It is similar to the SQL GROUP BY clause. Syntax var result = collection.GroupBy(x => x.Property); Example 1: Group Employees by Department var employees = new List { new Employee { Id = 1, Name = "John", Department = "IT" }, new Employee { Id = 2, Name = "David", Department = "HR" }, new Employee { Id = 3, Name = "Mike", Department = "IT" }, new Employee { Id = 4, Name = "Sara", Department = "HR" } }; var groupedEmployees = employees.GroupBy(e => e.Department); foreach (var group in groupedEmployees) { Console.WriteLine($"Department: {group.Key}"); foreach (var employee in group) { Console.WriteLine(employee.Name); } } Output: Department: IT John Mike Department: HR David Sara Example 2: Group and Count var result = employees .GroupBy(e => e.Department) .Select(g => new { Department = g.Key, EmployeeCount = g.Count() }); foreach (var item in result) { Console.WriteLine($"{item.Department} - {item.EmployeeCount}"); } Output: IT - 2 HR - 2 Example 3: Multiple Columns Grouping var result = employees.GroupBy(e => new { e.Department, e.City }); Equivalent SQL: SELECT Department, City, COUNT(*) FROM Employees GROUP BY Department, City; Query Syntax var result = from e in employees group e by e.Department into grp select new { Department = grp.Key, Count = grp.Count() }; Common Usage with Entity Framework var warrantySummary = db.tbl_asset_warranty .GroupBy(w => w.ClaimStatus) .Select(g => new { ClaimStatus = g.Key, TotalCount = g.Count() }) .ToList(); This returns the count of warranties grouped by ClaimStatus.

GroupBy in Linq

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