Converting a sqlserver to linq query

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I would like to know what is the correct way to convert this query to LINQ.

SQL

SELECT  DISTINCT ( CONVERT(date,FechaCreacion)) FROM Tabla
    where ID = 4
    order by CONVERT(date,FechaCreacion) desc 
    OFFSET     (0 * 20) ROWS    
    FETCH NEXT 20 ROWS ONLY  ;

With this query it brings me this data:

A1. 2021-03-16
 2. 2021-03-15
 3. 2021-03-14
 4. 2021-03-13
 5. 2021-03-11
 6. 2021-03-09
 7. 2021-03-02
 8. 2021-02-28
 9. 2021-02-25
 10. 2021-02-24
 11. 2021-02-23
 12. 2021-02-22
 13. 2021-02-21
 14. 2021-02-19
 15. 2021-02-10
 16. 2020-11-30
 17. 2020-10-05
 18. 2020-02-18

What I have tried:

LINQ:

C#

var query = (from sp in esquema.Tabla
                                 where sp.ID== 4
                                 orderby DbFunctions.TruncateTime(sp.FechaCreacion) descending
                                 select new
                                 {
                                    fechacreacion = DbFunctions.TruncateTime(sp.FechaCreacion)
                                 }
                                 ).Skip(0* 20).Take(20).ToList().Distinct();

With linq it brings me less data than the query made directly in sqlserver

1. 2021-03-16
2. 2021-03-15
3. 2021-03-14
4. 2021-03-13
5. 2021-03-11
6. 2021-03-09
7. 2021-03-02
8. 2021-02-28
9. 2021-02-25
10. 2021-02-24
11. 2021-02-23

Posted 15-Mar-21 8:48am

Jhon Daniel Guzman

Updated 15-Mar-21 10:47am

Maciej Los

v2

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Maciej Los · Accepted Answer · 2021-03-15T10:47:00

Solution 1

Replace this:

C#

).Skip(0* 20).Take(20).ToList().Distinct();

with:

C#

).Distinct().Take(20).ToList();

Why?
The first statement gets exactly 20 "rows", but some of them are duplicated. So, Distinct() method at the end of statement removes that duplicates.

Posted 15-Mar-21 10:47am

Maciej Los

Updated 15-Mar-21 23:49pm

v4

Comments

Richard Deeming 16-Mar-21 5:44am

Surely it would be better to move the Distinct before the Skip / Take calls? By calling ToList, you're loading the entire table into memory.

Maciej Los 16-Mar-21 5:49am

Ooops... It wasn't my intention to load entire table into memory, but only those 20 records.
Thanks for pointing me that out.

Jhon Daniel Guzman 25-Mar-21 1:21am

Thank you very much, that was the error I had

Maciej Los 25-Mar-21 3:12am

You're very welcome.