LINQ to SQL多个表左外部联接

这是使用LINQ实现左外部联接的方式。您应该使用GroupJoin（

join...into

from d in context.dc_tpatient_bookingdjoin bookingm in context.dc_tpatient_bookingm     on d.bookingid equals bookingm.bookingid into bookingmGroupfrom m in bookingmGroup.DefaultIfEmpty()join patient in dc_tpatient     on m.prid equals patient.prid into patientGroupfrom p in patientGroup.DefaultIfEmpty()// ... other joins herewhere d.processid == 6 &&      ((m.branchId == 1 && d.DestinationBranchID == 0) ||       (d.DestinationBranchID == 1 && d.sendstatus == "R"))// ... other conditions hereorderby d.priority descending, m.bookingidselect new {   d.bookingid,   d.labid,   d.processid,   p.prid,   p.prno,   m.bookingid // need for grouping} into xgroup x by x.bookingid into gselect g

该查询联接了三个表。您可以以相同的方式加入其余表。