linq query help

[Nick]

Hello,

I need some assistance with a LINQ query. I've got a simple query:

var q = from t in db.Table1 select t;

Based on user input I'm adding some where clauses:

if (condition1)
q = q.Where(t => t.Field1==1);
if (condition2)
q = q.Where(t => t.Field2==2);

Table1 has a sub table. Based on a condition I want find the Table1 records
that have one or more Table2 records. If I were using sql I would do
something like this:

select * from Table1 t1 where exists (select * from Table2 t2 where
t1.id=t2.id and t2.field1='somevalue')

How can I do this in LINQ given that I have added the above where clauses
based on those conditions?

Thanks,
Nick

 

[Frans Bouma [C# MVP]]

Hello,

I need some assistance with a LINQ query. I've got a simple query:

var q = from t in db.Table1 select t;

Based on user input I'm adding some where clauses:

if (condition1)
q = q.Where(t => t.Field1==1);
if (condition2)
q = q.Where(t => t.Field2==2);

Table1 has a sub table. Based on a condition I want find the Table1 records
that have one or more Table2 records. If I were using sql I would do
something like this:

select * from Table1 t1 where exists (select * from Table2 t2 where
t1.id=t2.id and t2.field1='somevalue')

How can I do this in LINQ given that I have added the above where clauses
based on those conditions?

Use the Queryable.Any extension method:
q=q.Where(t=>t.Table2s.Any(t2=>t2.Field1==someValue));

FB
--
------------------------------------------------------------------------
Lead developer of LLBLGen Pro, the productive O/R mapper for .NET
LLBLGen Pro website: http://www.llblgen.com
My .NET blog: http://weblogs.asp.net/fbouma
Microsoft MVP (C#)
------------------------------------------------------------------------

 

[Nick]

Thanks a lot for your help. This was exactly what I was looking for.

Thanks,
Nick