sql - Linq return nothing if nullable data is compared -

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i have column in database value null. , reading value in linq result linq not return result. linq looks 

dim result= (from t in <tablename> i.id=pid)

pid passed nothing , db consist id value null linq should return result not return. why ?

this query translated sql following clause:

where [t1].[id] = @p1

the problem here null comparison semantics in sql returns null, not true, , row filtered.

you want, instead, have clause:

where [t1].[id] null

which can different query.

dim result= (from t in <tablename> i.id nothing)

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