How to select Distinct values in LINQ c#?

How to select Distinct values in LINQ c#?

By Using LINQ we can read distinct values….LINQ: Read Distinct Record from Data Table

1. public JsonResult getEmpCity()
2. {
3. using (CompanyDBEntities dc = new CompanyDBEntities())
4. {
5. var query = (from p in dc. Emp_Information.
6. select p. City). ToList();
7. return new JsonResult.
8. {

How to Distinct list in c# LINQ?

LINQ Distinct operator is used for removing duplicates elements from the sequence (list). Distinct operator comes under Set operators category in LINQ query operators. For example, we have one collection A = { 1, 2, 3, 3, 4, 4, 5}.

How to find Distinct in LINQ?

You can make groups and get the first object from each group or you can use DistinctBy function to achieve the result.

1. LINQ DistinctBy() on a Property.
2. Using GroupBy and Select on a Property.
3. LINQ Distinct() – By Field.
4. LINQ GroupBy and Select Operators.
5. Using Select and Distinct operators.

Can we use group by with distinct?

Well, GROUP BY and DISTINCT have their own use. GROUP BY cannot replace DISTINCT in some situations and DISTINCT cannot take place of GROUP BY. It is as per your choice and situation how you are optimizing both of them and choosing where to use GROUP BY and DISTINCT.

How does Linq distinct work?

The Distinct() method works the same way as the DISTINCT directive in SQL. It returns a new sequence containing all the elements from the target sequence that are distinct from each other, as determined by the default equality comparer for the data type of the sequence.

Why distinct is not working in Linq?

10 Answers. LINQ Distinct is not that smart when it comes to custom objects. All it does is look at your list and see that it has two different objects (it doesn’t care that they have the same values for the member fields). One workaround is to implement the IEquatable interface as shown here.

Is GROUP BY better than distinct?

If you want to group your results, use GROUP BY, if you just want a unique list of a specific column, use DISTINCT.

Is GROUP BY faster than distinct?

DISTINCT is used to filter unique records out of all records in the table. It removes the duplicate rows. SELECT DISTINCT will always be the same, or faster than a GROUP BY.

Does Linq distinct preserve order?

Yes, Enumerable. Distinct preserves order. Assuming the method to be lazy “yields distinct values are soon as they are seen”, it follows automatically.

Does Linq distinct use equals?

Linq distinct doesn’t call Equals method.

Why is GROUP BY faster than distinct?

GROUP BY is also faster than DISTINCT in AWS Redshift, because GROUP BY uses a XN HashAggregate and DISTINCT uses a XN Unique . It is the same problem that older versions of Postgres have.

How to use group by in LINQ with single column?

Group by in linq with single column. Here is an example how we can use group by clause based on single column. var groupScores = from techStream in studentsStream group techStream by techStream.StreamId into studentGroup select new { Stream = studentGroup.Key, GroupScore = studentGroup.Sum (x => x.Score), }; foreach (var scr in groupScores) {

How to use the LINQ groupby method in C #?

How to use the GroupBy Method along with OrderBy Method in C# using both Method and Query Syntax? What is Linq GroupBy Method in C#? The Linq GroupBy in C# belongs to the Grouping Operators category and exactly does the same thing as the Group By clause does in SQL Query.

How to get the results of a LINQ query?

By a single property. By the first letter of a string property. By a computed numeric range. By Boolean predicate or other expression. By a compound key. In addition, the last two queries project their results into a new anonymous type that contains only the student’s first and last name.

How to organize students into groups in LINQ?

The following example organizes the students into groups based on their branch (i.e. branch will act as the key). That means students with the same branch will be stored in the same group where each group having a key and an inner collection. Here, the key will be branch and the collection will be the student belongs to that particular branch.

https://www.youtube.com/watch?v=U6cWBnkeTro