I have a LINQ query that performs some joins on other tables, but I need to perform a check on a Join condition in order to know if a field is null, because if it is null I have to join with the same table but on another field.
I have this LINQ query :
var fasi = _fasi.Split(';').Select(n => short.Parse(n)).ToList();
listaDoc = (
from Documenti in db.Documenti
join Tipi in db.Tipi
on new { C = (int)Documenti.Classe, C_Tipo = Documenti.CTipo }
equals new { Tipi.C, Tipi.C_Tipo } into Tipi_join
from Tipi in Tipi_join.DefaultIfEmpty()
join Stipi in db.Stipi
on new { C = Documenti.Classe, C_STipo = Documenti.CSTIpo }
equals new { Stipi.C, Stipi.C_STipo } into Stipi_join
from Stipi in Stipi_join.DefaultIfEmpty()
join PathClassi_Web in db.PathClassi_Web on new { cod_class = Documenti.Classe } equals new { cod_class = PathClassi_Web.cod_class } into PathClassi_Web_join
from PathClassi_Web in PathClassi_Web_join.DefaultIfEmpty()
where
(fasi).Contains((short)Documenti.Stato)
select new
{
Documenti.ID,
Documenti.Data,
Documenti.Descrizione,
Documenti.DAL,
Documenti.AL,
Documenti.Stato,
Documenti.NomeDoc,
Classe = (int?)Documenti.Classe,
Documenti.CTipo,
Documenti.CSTIpo,
Documenti.SiglaRed,
Documenti.Stipula,
Documenti.DataCmp,
Documenti.Regione,
Documenti.NumDoc,
Documenti.Destinazione,
Documenti.DataStampa,
Documenti.Ext,
GRP2 = Tipi.GRP2,
DESCRIZ = Stipi.Descriz,
DESCR_CLASS = PathClassi_Web.descr_class
});
I need to know if Tipi.C_Tabella
is null. If not, I will join Documenti
and Tipi
"on Tipi.C_Tabella = Documenti.CTipo
, but if it is null I will join Documenti
and Tipi
on Tipi.C_Tipo = Documenti.CTipo
.
How can I do this by modifying my LINQ query written above?
from Documenti in db.Documenti
join Tipi in db.Tipi
on new { C = (int)Documenti.Classe, C_Tipo = Documenti.CTipo }
equals new { Tipi.C, Tipi.C_Tabella ?? Tipi.C_Tipo } into Tipi_join
OR
from Documenti in db.Documenti
from Tipi in db.Tipi
where (Tipi.C_Tabella ?? Tipi.C_Tipo) = Documenti.CTipo
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