24 hours of values

Question

I have a sql table : date (Y-m-d) / time (00:00:00) / power (INT)

When I select a date from an inline datepicker, I am trying to post 3 HighCharts graph (one-24 hours, t

Answer 1

You need a loop to walk over the rows:

$sql = "
SELECT HOUR(time) as h, power
FROM feed 
WHERE date = '".$choice."' 
ORDER BY HOUR(time)"; 

$res = mysql_query($sql) or die('sql='.$sql."\n".mysql_error()); 

while($row = mysql_fetch_assoc($res)) {
    echo $row['h'].":".$row['power']'<br />'; 
}

This will give you the power per day for a given month:

$sql = "
SELECT DAY(date) as d, SUM(power) as powerday
FROM feed 
WHERE MONTH(date) = '".$month."' 
GROUP BY DAY(date) 
ORDER BY DAY(date)"; 

$res = mysql_query($sql) or die('sql='.$sql."\n".mysql_error()); 

while($row = mysql_fetch_assoc($res)) {
    echo $row['d'].":".$row['powerday']'<br />'; 
}

Answer 2

At the moment, your SELECT gives you only the results which happened exactly 24 hours before the current moment. What you need is a range. Example for 1 hour (indentation added for clarity):

WHERE `time` BETWEEN 
   DATE_SUB('".$choice."', INTERVAL 24 HOUR) 
   AND DATE_SUB('".$choice."', INTERVAL 23 HOUR) 

This way, you'll get results with time in the 1-hour range of "now - 24 hours" and "now - 23 hours". The BETWEEN operator is equivalent to this:

WHERE `time` >= DATE_SUB('".$choice."', INTERVAL 24 HOUR)
   AND `time` <= DATE_SUB('".$choice."', INTERVAL 23 HOUR) 

Answer 3

Thank you everyone for all your help !

The problem was in the first string, I only had to change the date format in addition to your wonderful examles !

$choice = (isset($_POST['choice'])) ? date("m",strtotime($_POST['choice'])) : date("m"); 

Thank You Very Much !

Alan