SQL to LINQ Conversion of coalesce

Question

This is my SQL query:

select 
   S.student_No, 
   coalesce(P.Name,'0'),
   P.Surname 
from 
   Person as P 
join 
   Student as S 
       on P.Id = S.Person_Id

I want to convert it LINQ , i did it except coalesce function,

from P in cbu.PERSON
join S in cbu.STUDENT on P.ID equals S.PERSON_ID
select new
{
     S.Stundent_No,
     P.Name,
     P.Surname,
};

how can I use coalesce in this linq query

score 0 · Answer 1 · answered Oct 07 '13 at 13:01

0

P.Name ?? "0". C# has the coalesce operator built-in. Even if you didn't know that, you could use the ?: operator.

The join is not necessary, btw. You can just write P.Student.Stundent_No (or whatever the properties are called).

answered Oct 07 '13 at 13:01

usr

I tried it but i get this error -> Operator ?? cannot be applied to operands of type 'int' and 'string' – Taha Karaca Oct 07 '13 at 13:21
What do you think is the cause of that error message? It is a compiler error. – usr Oct 07 '13 at 13:39
i've written instead of P.Name ?? "0",--> PERSON_NAME=P.Name ?? '0' , it works but, all null fields become 48 .. – Taha Karaca Oct 07 '13 at 13:48
And also if i write PERSON_NAME=P.Name ?? ' ' like this , at this time all null fields become 32 – Taha Karaca Oct 07 '13 at 13:51
Finally it works when i write like this -> PERSON_NAME=P.Name ?? 0 – Taha Karaca Oct 07 '13 at 13:57
`''` is a char literal. You want a string literal (`""`). – usr Oct 07 '13 at 14:01
It also seems strange that PERSON_NAME is an int?! Why is that? It sounds like a string. – usr Oct 07 '13 at 14:19

1 Answers1