LINQ inserts 'ESCAPE N'~' in query

Question

When I examine the sql query the linq spits out, I noticed that it places a ESCAPE N\'~\' when doing a LIKE command. How do I get rid of this? It seems like the query take

Answer 1

Apparently,

var SearchPhrase = "xyz";
var result = (from I in db.myTabl
          where i.col1.contains(SearchPhrase)
          select I).toList();

will add ESCAPE N'~' in the underlying query.

However using a constant filter like the following, doesn't produce escape characters in the underlying query

var result = (from I in db.myTabl
          where i.col1.contains("xyz")
          select I).toList();

Which means, variable filters are escaped, while constants are not.

So, in this case, we need a variable to be used as a constant filter.

Using the following, shouldn't add any escape characters:

var SearchPhrase = "xyz";
var result = (from I in db.myTabl
          where SqlMethods.Like(i.col1, string.Format("%{0}%", SearchPhrase))
          select I).toList();

but this works only with LINQ to SQL.

The other alternative is to embed the variable value as a constant, which is done using the following as explained in the SO article

Answer 2

If you use LINQ 2 Entities, use SqlQuery to remove the "~" character.

Just append the value to compare like an ordinary sql query.

For example:

var resultList = context.TableName.SqlQuery(
                "SELECT * FROM TableName WHERE field LIKE '%" + fieldValue+ "%' ").ToList();

Answer 3

Linq to Sql use '`' as it's default escape character when doing like comparisons. It will only cause a problem if your string actually contains ~ characters.

Use SqlMethods.Like to override this.