show mysql average of the last 14 days in a c# application - mysql

Question

I have a mysql table with the columns ID, name, gold and timestamp.
This table shows with the following statement the average of the gold of the respective item(name). But now the database is already filled with 90k entries and the average should only be limited to 2 weeks. Here is the code:
`
private DataTable GetAverageGold()
{
var dtAverageGold = new DataTable();
var percentageBuy = double.TryParse(textBox1.Text.Replace("%", string.Empty), out var sell) ? sell / 100 : 0.02;
using (_con = GetMySqlConnection())
{
using (var cmd = new MySqlCommand(
"SELECT name AS name, FORMAT(GROUP_CONCAT(gold ORDER BY id DESC), 'de_DE') AS 'MOST RECENT', FORMAT(ROUND(AVG(gold) - AVG(gold) * " +
percentageBuy.ToString(CultureInfo.InvariantCulture).Replace(",", ".") +
"), 'de_DE') AS Einkaufspreis, FORMAT(ROUND(AVG(gold)),'de_DE') AS Durchschnitt, ROUND((AVG(gold) - GROUP_CONCAT(gold ORDER BY id DESC)) / GROUP_CONCAT(gold ORDER BY id DESC) * 100,2) AS 'profit in %' FROM items GROUP BY name ORDER BY Name",
_con))
{
try
{
_con.Open();
var reader =
cmd.ExecuteReader();
dtAverageGold.Load(reader);
}
catch (MySqlException ex)
{
MessageBox.Show(ex.ToString(), "Error in: GetAverageGold", MessageBoxButtons.OK,
MessageBoxIcon.Error);
}
finally
{
_con.Close();
}
}
}
return dtAverageGold;
}
`
I tried "WHERE timestamp <= NOW() + INTERVAL 14 DAY GROUP BY name ORDER BY name" at the end of the statement. but it did not help. The syntax seems to be correct, as I get no error, but the average still refers to all entries

Answer 1

You were thinking along the right lines but it should have been -
WHERE timestamp >= NOW() - INTERVAL 14 DAY
or
WHERE timestamp >= CURRENT_DATE - INTERVAL 14 DAY