Handling ExecuteScalar() when no results are returned

Question

I am using the following SQL query and the ExecuteScalar() method to fetch data from an Oracle database:

sql = \"select username from usermst wh         


        

Answer 1

I'm using Oracle. If your sql returns numeric value, which is int, you need to use Convert.ToInt32(object). Here is the example below:

public int GetUsersCount(int userId)
{
    using (var conn = new OracleConnection(...)){
        conn.Open();
        using(var command = conn.CreateCommand()){
            command.CommandText = "select count(*) from users where userid = :userId";
            command.AddParameter(":userId", userId);            
            var rowCount = command.ExecuteScalar();
            return rowCount == null ? 0 : Convert.ToInt32(rowCount);
        }
    }
}