Dynamic X-axis graph that will change according to the count of rows - php

Question

Let's say I have a mysql table with an id, some measurements and a DATE column.
Example: id, measurements, date_entered
This table stores some measurements of a patient so as to keep a record for him.
I want to make a graph which according to the count of rows that exist in the database will change dynamically the X-axis.
For example, if there are only 7 rows in the table I need to represent 7 days to the graph with the measurement for every day. If there are more than 14 days, I want it to change to respresent 2 weeks on X-axis and the average measurements(average for 1 week and average for the other too) on Y-axis and so on from weeks to months.
Can anyone help me on this? I cannot think of something that will do in my case..
I use JPGraph to make the line graph but i don't have a problem there. My problem is on how to handle the results.
I hope you will understand what I need! Thanks.

Answer 1

Something like this?
// Get the results from the database
$query = "SELECT `data_col` FROM `table` WHERE `condition_col` = 'some value'";
$result = mysql_query($query);
// Get all results into array and count them
$results = array();
for ($i = 0; $row = mysql_fetch_assoc($result); $i++) {
$results[] = $row;
}
// Re-format the data depending on number of results
$data = array();
if ($i < 14) { // Less than 14 days, show per day
foreach ($results as $row) {
$data[] = $row['data_col'];
}
} else if ($i < 56) { // Less than 8 weeks, show per-week
$thisweek = array();
for ($j = 0; isset($results[$j]); $j++) { // Loop the results
$thisweek[] = $results[$j]['data_col']; // Add result to this week total
if ($j % 7 == 0 && $j > 0) { // Every 7 days...
$data[] = array_sum($thisweek) / 7; // ...calculate the week average...
$thisweek = array(); // ...and reset the total
}
}
// If there is an incomplete week, add it to the data
$data[] = array_sum($thisweek) / count($thisweek);
} else { // 8 weeks or more, show per-month
$thismonth = array();
for ($j = 0; isset($results[$j]); $j++) { // Loop the results
$thismonth[] = $results[$j]['data_col']; // Add result to this month total
if ($j % 28 == 0 && $j > 0) { // Every 28 days...
$data[] = array_sum($thismonth) / 28; // ...calculate the month average...
$thismonth = array(); // ...and reset the total
}
}
// If there is an incomplete month, add it to the data
$data[] = array_sum($thismonth) / count($thismonth);
}
// $data now contains an array from which you should be able to draw your
// graph, where array keys are (sort of) x values and array values are y
// values.
Obviously, this solution assumes a 28-day month - it does not use the calendar, simply the number of days. You could do something horrible involving working out the stats based on some values returned by date() or similar, but this would likely drastically increase the calculation overhead and slow the process down.
Hopefully this will give you a place to start.