How to Select Random Rows in a data table of C#?

Question

My query is like this:

select top 50 Empid from (Select top 50 Empid from Emp inner join campus on Emp.CampusId=campus.CampusId join departments on Emp.department=departments.deptid where campus.Cname='Mumbai' ) x order by NEWID();

But Here the number 50 is not constant it is variable(calculted value). So, I want get all the Empids in one datatable and then I need to select few of them randomly (In the above example 50)..Is it possible to do using dataview??

do you wish to do in C# or SQL server ?? – Dhaval Dec 24 '13 at 12:28 — Dhaval, Dec 24 '13 at 12:28

score 0 · Answer 1 · edited May 23 '17 at 11:56

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This has been answered before.

Is using Random and OrderBy a good shuffle algorithm?

Please see Fisher-Yates shuffle implemented by Jon Skeet.

Basically, randomly shuffle the row numbers or ids, choose little n out of population N.

edited May 23 '17 at 11:56

Community

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answered Dec 24 '13 at 13:49

CRAFTY DBA

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score 0 · Answer 2 · answered Dec 24 '13 at 13:54

0

In T-SQL, You can use SELECT TOP (@variable) instead of SELECT TOP 50 as below:

Declare @RecCount int 

--//Set the variable @RecCount here

--//Use it to bring the top record as follows
Select top (@RecCount) Empid 
From Emp inner join campus on Emp.CampusId=campus.CampusId 
               join departments on Emp.department=departments.deptid 
Where campus.Cname='Mumbai'
Order by NEWID();

answered Dec 24 '13 at 13:54

Kaf

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For example if this query returns 400 records, but I need to select only top 200 rows of which top 50 should be shuffled.. – user3116746 Dec 24 '13 at 16:32

How to Select Random Rows in a data table of C#?

2 Answers2