JpGraph: Create a PHP Bar chart using MySQL data

Question

By taking mysql database table values, want to create PHP a bar chart. I used JpGraph to draw the bar chart. I want to take data from 'student' table. I has a column named 'category' in which the value is either 'Full time' or 'Part time'. I want to count the no. of rows in which the category is 'Full time' and no.of rows in which the category is 'Part time'. The x-axis should be category and y-axis should be relevant number of rows. The PHP code is as follows;

<?php
 require_once('/jpgraph-3.5.0b1/src/jpgraph.php');
 require_once('/jpgraph-3.5.0b1/src/jpgraph_bar.php'); 
 $db = mysql_connect("localhost", "root","") or die(mysql_error());

 mysql_select_db("mphildatabase",$db) or die(mysql_error());

 $sql1 = mysql_query("SELECT category FROM student") or die(mysql_error());
 $sql2 = mysql_query("SELECT COUNT(*) FROM student WHERE category='Full Time'") or die(mysql_error());
 $sql3 = mysql_query("SELECT COUNT(*) FROM student WHERE category='Part Time'") or die(mysql_error());
 while($row1 = mysql_fetch_array($sql1))
 {
 $row2 = mysql_num_rows($sql2);
 $row3 = mysql_num_rows($sql3);
 $data[] = $row2;
 //$data[] = $row3;
 $leg[] = $row1['category'];
 }
 $graph = new Graph(950,750,"auto");
 $graph->SetScale("textint");
 $graph->img->SetMargin(50,30,50,50);

 $graph->SetShadow();

  $graph->xaxis->SetTickLabels($leg);

  $bplot = new BarPlot($data);
  $bplot->SetFillColor("lightgreen"); 
  $bplot->value->Show();
  $bplot->value->SetFont(FF_ARIAL,FS_BOLD);
  $bplot->value->SetAngle(45);
  $bplot->value->SetColor("black","navy");

  $graph->Add($bplot);
  $graph->Stroke(); ?>

This will give a graph of seperate bars for each row. There will be bars printed for each row and y-axis value of all those bars will be 1. How can I draw a bar graph with only 2 bars, one showing no.of rows in which the category is 'Full Time' and other bar showing no.of rows in which the category is 'Part Time'? Thank you!

chessar · Accepted Answer · 2013-11-17 17:52:16Z

1

You must use just one query, and fill the arrays in one loop. Your query must be:

"SELECT count(*) as num_rows, category from 
student WHERE category ='Full Time' or Category= 'Part Time'
Group by Category
  "

...

while($row1 = mysql_fetch_array($sql1))
{
$leg[] = $row1['category'];
$data[] = $row1['num_rows']
}

answered Nov 17, 2013 at 17:52

chessar

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2 Comments

Dakshila Kamalsooriya Over a year ago

This will give an error message as 'Either X or Y data arrays contain non numeric values. Check that data is really specified as numeric data and not as strings'. Why is that?

Dakshila Kamalsooriya Over a year ago

solved! Changed the arrays as $leg[] = $row1['num-rows']; $data[] = $row1['category']; . Thank you @chessar.

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