OleDbDataAdapter dataAdapter = new OleDbDataAdapter(
    "SELECT accounts.ID, uname, firstname, lastname, description FROM accounts, profiles " +
    "WHERE accounts.ID = profiles.ID AND uname like '*@uname*'", connection);
dataAdapter.SelectCommand.Parameters.Add("@uname", OleDbType.VarChar).Value = tbxFilter.Text;

WHERE accounts.ID = profiles.ID AND uname like @uname

dataAdapter.SelectCommand.Parameters.Add("@uname", OleDbType.VarChar).Value = "%" + tbxFilter.Text + "%"

dataAdapter.SelectCommand.Parameters.Add("@uname", OleDbType.VarChar).Value = "*" + tbxFilter.Text + "*".

tbxFilter.Text.Replace("'", "''")