linq to sql join on multiple columns using lambda

Question

Can someone help me to translate this

var query = from s in context.ShoppingMalls
join h in context.Houses
on
new { s.CouncilCode, s.PostCode }
equals
 new { h.CouncilCode, h.PostCode }
select s;

into lambda query?

Thanks.

Thomas Levesque · Accepted Answer · 2012-04-25 13:53:28Z

61

var query = context.ShoppingMalls
                   .Join(
                       context.Houses,
                       s => new { s.CouncilCode, s.PostCode },
                       h => new { h.CouncilCode, h.PostCode },
                       (s, h) => s);

answered Apr 25, 2012 at 13:53

Thomas Levesque

294k73 gold badges639 silver badges769 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Alex Fairchild Over a year ago

edited to give the anonymous objects keys, so that the compiler can infer that the types are the same.

JoshNaro Over a year ago

I don't know where your edit went, but if the names and types aren't the same you can do something like this for both of the join on objects so that the property names match: new { cc = s.CouncilCode, pc = s.PostCode }

JoeCo · Accepted Answer · 2018-04-30 23:25:31Z

23

Although the example and answer given by @Thomas Levesque works for columns that match, I wanted to also supply the answer if you have columns to join on but they have different names. This is what I needed for my googling and this question got me close.

The difference of course is the explicit declaration of the columns as a variable to identify on.

var query = context.MapKitsToResources
              .Join(
                     context.Resources, 
                     o => new { Id = o.ResourceId, Type = o.ResourceTypeId},
                     i => new { Id = i.Id, Type = TypeId},
                     (o, i) = new { rType : i };

answered Apr 30, 2018 at 23:25

JoeCo

7056 silver badges13 bronze badges

2 Comments

Sanjay_Umeda Over a year ago

Agree with you for explicit give name to joined columns. Great answer.

PVIJAY Over a year ago

This is the perfect solution to avoid ambiguity between similar columns and match exact columns

Collectives™ on Stack Overflow

linq to sql join on multiple columns using lambda

2 Answers 2

2 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related