how to read varbinary max sql server

Question

I have this query:

CREATE PROCEDURE [dbo].[spGetUserAvatar]
    ( @userid int)  
     AS 
      BEGIN
        select avatar
          from t_user
             where (userID = @userid) AND (avatar<>null)
       end

and this C# code to execute this query:

string ConnectionString = SafaConnectionString.ConnectionString;
    SqlConnection Connection = new SqlConnection(ConnectionString);
    SqlCommand cmd = new SqlCommand("spGetUserAvatar", Connection);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.AddWithValue("@userid", userid);
    DataTable dt = new DataTable();
    SqlDataAdapter sda = new SqlDataAdapter();
    try
    {
        cmd.Connection = Connection;
        Connection.Open();            
       sda.SelectCommand = cmd;
        sda.Fill(dt);
        if (dt.Rows.Count > 0)
            return dt;
        else
            return null;
    }

It worked fine,but now returns dt.Rows.Count == 0.In the event that, t_users.avatar Is not empty. Have I got the query wrong?

maybe your table has been truncated? – ken lacoste Aug 23 '15 at 15:27 — ken lacoste, Aug 23 '15 at 15:27

score 0 · Accepted Answer · answered Aug 23 '15 at 15:25

0

You cannot compare NULL with <> operator use IS operator to validate NULL values

where userID = @userid AND avatar is not null

answered Aug 23 '15 at 15:25

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how to read varbinary max sql server

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