Compile error on simple compound conditional in LINQ to SQL join

Question

For some reason I am getting a "Query body must end with a select clause or a group clause" compile error on what seems to be a simple compound conditional in the following linq-to-sql query:

using (var db = new CaremcDB(Database.Conn))
{
 var taxids = from p in db.ProviderTaxIds 
      join c in db.CustomerProviders
      on customerId equals c.CustomerId && p.Id equals c.ProviderId
      select p;

 return taxids.ToList<ProviderTaxIds>();
}

It chokes on the "&& p.Id equals c.ProviderId" clause for some reason.

Using == instead of equals creates a different error: "The name 'p' is not in scope on the right side of 'equals'" — BillyM2010, Jul 05 '11 at 16:22
how about adding parenthesis around customerId equals c.CustomerId && p.Id equals c.ProviderId — boca, Jul 05 '11 at 16:23
I get the following errors when using parenthesis: 1. ) expected 2. Invalid expression term ')' 3. A query body must end with a select clause or a group clause 4. : expected — BillyM2010, Jul 05 '11 at 16:33
is `customerId` a different input or should it have been `p.customerId`? — Anthony Pegram, Jul 05 '11 at 16:40
See [This Question](http://stackoverflow.com/questions/345427/linq-to-sql-join-multiple-columns-from-the-same-table) for answers — The Scrum Meister, Jul 05 '11 at 16:41

score 3 · Accepted Answer · answered Jul 05 '11 at 16:41

3

It appears that customerId is an external input to the query. Move that to a where clause.

...
on p.Id equals c.ProviderId  
where customerId == c.CustomerId
select p;

answered Jul 05 '11 at 16:41

Anthony Pegram

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That works for some reason. But it also compiles if I remove the "&& p.Id equals c.ProviderId" (which isn't what I want, but just testing the ability to compile.) It is very puzzeling as it seems this should be rather straight-forward. – BillyM2010 Jul 05 '11 at 16:52
@Billy, The `&&` portion is the problem. Another user posted a way to do a compound-field join via anonymous typing, but you really don't need to do that in this specific case. – Anthony Pegram Jul 05 '11 at 16:55
Using the where clause works. I take it that && is not allowed on a join for some reason. – BillyM2010 Jul 05 '11 at 17:41

score 1 · Answer 2 · answered Jul 05 '11 at 16:52

1

try this, the parameter names just need to match in the anonymous object

join c in db.CustomerProviders on new { customerId, p.Id } equals new { customerId = c.CustomerId, Id= c.ProviderId }

answered Jul 05 '11 at 16:52

Jeremy Gray

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Compile error on simple compound conditional in LINQ to SQL join

2 Answers2