Select random row without duplication using entity framework4.5 mvc4

Question

I have tried following code i need to random row with out duplication based on the NAME field.

List list = db.Logos.Where(a => a.LogoName != "empty.png").OrderBy(r => Guid.NewGuid()) .GroupBy(a => a.LogoName) .Select(g => g.FirstOrDefault()).Take(8).ToList();

but i did not get randomly but i have tried another code which is shuffling correctly but duplicate code could not apply, code below

List list = (from c in db.Logos where c.LogoName != "empty.png" select c).OrderBy(r => Guid.NewGuid()).Take(3).ToList();

please help how to select both duplication and random rows.

Muralidharan Deenathayalan · Accepted Answer · 2013-08-16 09:33:46Z

2

Can you please try the below one?

var result = (from logo in db.Logos
             where (logo.LogoName != "empty.png")
             orderby logo.LogoName
             select logo).Distinct();

answered Aug 16, 2013 at 9:33

Muralidharan Deenathayalan

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3 Comments

Sajith Over a year ago

This code is fine but i need randomly select rows with that code

Muralidharan Deenathayalan Over a year ago

Do you want random records, for each query execution?

Muralidharan Deenathayalan Over a year ago

Are you storing the previous query result somewhere?

usr · Accepted Answer · 2013-08-16 13:49:25Z

0

You are doing the ordering before the grouping. That looses the ordering completely.

db.Logos
.Where(a => a.LogoName != "empty.png")
.GroupBy(a => a.LogoName)
.Select(g => g.FirstOrDefault())
.OrderBy(r => Guid.NewGuid())
.Take(8)
.ToList();

Performance of this query will not be so great, but that does not seem to be your primary concern. It will be fast on small data sets.

answered Aug 16, 2013 at 13:49

usr

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