I want to remove the duplicated values from the columns ” 1)LabelName, 2)OpenLabelStandard, 3)Type “. The issue is that my table has four columns. beside to the three previous columns I have another one called 4)’Distance’. it is not a field from database. I added it to my table using some calculations in view model. the distance column is changeable for each row so when I’m using Distinct(), it is NOT working because of distance column.

for example, Currently I have like this table below.

LabelName OpenLabelStandard Type Distance A1 A2 A3 30 A1 A2 A3 50 A1 A2 A3 100 B1 B2 B3 15 B1 B2 B3 60

I need the result to be like the following

LabelName OpenLabelStandard Type Distance A1 A2 A3 30 B1 B2 B3 15

This is my select in controller.

var listdata = (from c in _context.OpenLabelTag select c ) .Select(x=> new {x.LabelName,x.OpenLabelStandard,x.Type, Distance = x.Coordinates.Distance(searchArea),x.Coordinates}) .OrderBy(s=>s.Coordinates.Distance(searchArea)) .Where(x=>x.Coordinates.IsWithinDistance(searchArea,InputRadius) && x.OpenLabelStandard !=null) .Take(10).ToList().Distinct() ;

Do you have any clue how can I solve it ?

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## Answer

You can’t apply distinct to a subset of properties and still keep the rest of the properties because distinct “groups” values. Other properties that are not included in the distinct result cannot be part of the result because they might have multiple, different values (like your Distance example).

As HoneyBadger suggested, you can simulate a distinct with a `GroupBy()`

, then select all the `.Key`

properties and compute aggregate functions on the rest of the properties:

var listdata = (from c in _context.OpenLabelTag select c) .Select(x => new { x.LabelName, x.OpenLabelStandard, x.Type, Distance = x.Coordinates.Distance(searchArea), x.Coordinates }) .Where(x => x.Coordinates.IsWithinDistance(searchArea, InputRadius) && x.OpenLabelStandard != null) .GroupBy(x => new { x.LabelName, x.OpenLabelStandard, x.Type }) .Select(gr => new { gr.Key.LabelName, gr.Key.OpenLabelStandard, gr.Key.Type, MinDistance = gr.Min(x => x.Distance) }) .OrderBy(s => s.MinDistance) .Take(10).ToList();

Note that I removed the `Distinct()`

and also moved the `OrderBy()`

to after the grouping operation.