select * only return one value - sql-server

Question

I want select multiple (all) values from table Account.
string query = "SELECT * FROM Account";
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand(query, connection);
SqlDataReader reader;
connection.Open();
reader = command.ExecuteReader();
reader.Read();
label1.Text = reader["PasswordHash"].ToString();
connection.Close();
Why is this always returning only the first row. Actually it return one row, because if I set in where clause something like where id = 2 and id = 3 it still returns only one value.
Table have more than one value i checked form Management Studio, there query run as they should.
Thanks in advance.

Answer 1

Because you are not looping through the query results, it shows up only one result.
string query = "SELECT * FROM Account";
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand(query, connection);
SqlDataReader reader;
connection.Open();
reader = command.ExecuteReader();
While(reader.Read())
{
label1.Text += " " +reader["PasswordHash"].ToString();
}
connection.Close();
The above code loops through the query results and will give you what you want in a concatenated string assigned to label1.text. You can also view the results by inserting Console.WriteLine(reader["PasswordHash"].ToString()); in the while loop

Answer 2

You should do
while (reader.Read())
// process information
You need to iterate all the information you retrieved.
Sidenote: Use using statements on your SqlConnection, SqlCommand, and SqlDataReader to make sure the objects get disposed correctly.

Answer 3

The reader only advances one record at a time. You'd need to iterate through the result set in a loop:
while (reader.Read()) {
// do something with the current row by accessing reader[]
}
reader.Close();
There are better ways to structure your code but this illustrates the point you were missing and requires the least changes.

Answer 4

You need to loop, something like this:
SqlDataReader reader = command.ExecuteReader();
// Call Read before accessing data.
while (reader.Read())
{
Console.WriteLine(String.Format("{0}, {1}",
reader[0], reader[1]));
}
There is an example in the MSDN docs:
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.aspx

Answer 5

The line reader.Read() will get the next row, so you can use while(reader.Read()) to iterate over the rows.

Answer 6

Looking at your code my recommendation is to use some other object to add the code to. Text of a label is not an appropriate choice.
Try using a foreach loop into a list to retrieve all the data that has been returned.

Answer 7

You need a while-loop;
while(reader.Read()) {
Console.WriteLine("{0}", reader[0]);
}

Answer 8

Using where id = 2 and id = 3 would return zero results as as id=2 and id=3 are mutually exclusive. where id = 2 or id = 3 could work.
while (reader.Read()) { /*Do stuff with current row*/ }
could work for iterating through the results

Answer 9

You need to loop and data reader is best way for your code , for sample ,something like this:
SqlDataReader myReader = myCommand.ExecuteReader();
// Always call Read before accessing data.
while (myReader.Read()) {
Console.WriteLine(myReader.GetInt32(0) + ", " + myReader.GetString(1));
}
// always call Close when done reading.
myReader.Close();