SqlDataReader.HasRows return always "true" even with empty result

Question

After browsing a multitude topics on the phenomenon of SqlDataReader.HasRows which always returns true even with empty result (and especially when it is about an SQL query with an aggregate), I dry completely on my code

However my example is very simple and HasRows returns True, FieldCount returns 1 even when there is no phpMyAdmin side line.

query = "SELECT FK_BarId FROM tlink_bar_beer WHERE FK_BeerId = " + sqlDataReader.GetInt32(0);

MySqlConnection sqlConnexionList = new MySqlConnection("server=localhost;database=beerchecking;uid=root;password=;");
MySqlCommand commandList = new MySqlCommand(query, sqlConnexionList);
sqlConnexionList.Open();

int[] BarsIds;
using (MySqlDataReader sqlDataReaderList = commandList.ExecuteReader())
{
    if (sqlDataReaderList.HasRows)
    {
        try
        {
            BarsIds = new int[sqlDataReaderList.FieldCount];
            int counter = 0;

            if (sqlDataReaderList.Read())
            {
                while (sqlDataReaderList.Read())
                {
                    int id = sqlDataReaderList.GetInt32(counter);
                    BarsIds[counter] = id;
                    counter++;
                }
            }
        }
        finally
        {
            sqlDataReaderList.Close();
        }
    }
    else
    {
        BarsIds = new int[0];
    }
}

sqlConnexionList.Close();

Do you know how to get HasRows false when there is no rows like in phpMyAdmin result?

Thanks for reading.

What happens when you run your query directly with SQL studio? I'll bet it returns a single row. — Koby Douek, Mar 28 '19 at 10:17
Something seems to be amiss. The query is constructed getting an ID from a `sqlDataReader`, so I assume the ID exists and you therefore have rows? `FieldCount` returns the number of columns and since the query has one column `FK_BarId` you'd always get 1. — J.R., Mar 28 '19 at 10:29

score 1 · Answer 1 · answered Mar 28 '19 at 11:09

1

I prefer to use an auxiliar DataTabe instead DataReader, something like this:

DataTable dt = new DataTable();
dt.Load(commandList.ExecuteReader());

if(dt.Rows.Count > 0){

    //rows exists
}else{

    //no rows
}

answered Mar 28 '19 at 11:09

Álvaro Briz

26
2

SqlDataReader.HasRows return always "true" even with empty result

1 Answers1