Why is LINQ to SQL converting my string parameter to a column name?

Question

This Linq to SQL query ...

    Return (From t In Db.Concessions Where t.Country = "ga" Select t.ConcessionID, t.Title, t.Country)

... is generating this SQL:

SELECT [t0].[ConcessionID], [t0].[Title], [t0].[Country]
FROM [dbo].[Concessions] AS [t0]
WHERE [t0].[Country] = ga

... when what I want is

WHERE [t0].[Country] = 'ga'

Any ideas why?

Answer 1

the select should be

Select New With {t.ConcessionID, t.Title, t.Country}

rather than

Select t.ConcessionID, t.Title, t.Country

you need to create a new instance of an anonymous type to contain the fields.

Answer 2

Wild guess.... could it be?

t.Country = "ga"

vs.

t.Country == "ga"

Answer 3

Actually, it shouldn't be generating either of those. It would convert the constant into a parameter, so it would be:

SELECT [t0].[ConcessionID], [t0].[Title], [t0].[Country]
FROM [dbo].[Concessions] AS [t0]
WHERE [t0].[Country] = @p0

with @p0 passed as 'ga'. could that be that you are seeing?

Answer 4

Answer

The Country field was a char(2); I changed it to nvarchar(50), and that fixed the problem. Is this a bug in Linq to SQL?

Answer 5

I cannot be sure about this particular example, but there is a known bug that causes similar problems with nvarchar(1) fields. It may be related.

There is a bug report here about it and I also wrote about it on my own site too.