EF left or right join

Question

User1183902823 posted

see the query

var answer = (from c in db.customers 
              join p in db.purchases 
              on c.ID = p.CustomerID into subs
              from sub in subs.DefaultIfEmpty()
              group sub by new { c.ID, c.Name } into gr
              select new {
                  gr.Key.ID,
                  gr.Key.Name,
                  Total = gr.Count(x => x != null),
                  CountCompleted = gr.Count(x => x != null && x.CompletedTransaction)
              }).ToList();

the above join is left or right join?

i got the above join hint from these url

https://stackoverflow.com/a/8055893/6188148
https://stackoverflow.com/a/46947013/6188148

how to determine what kind of join is it ?

thanks

Answer 1

User1400794712 posted

Hi tridip1974,

Actually, the code you post here can be said both left and right join.

For customers and purchases, it's left join.

For purchases and customers, it's right join.

There is no obvious division between them.

Best Regards,

Daisy

Answer 2

User1183902823 posted

you said --

For customers and purchases, it's left join.

For purchases and customers, it's right join.

this is not clear what you try to say.

it is very confusing that we can not say the join is left or right. it would be great if we could use left or right keyword at the time EF linq join query.