Double column Highcharts with drilldown - charts

Question

I am using Highcharts for generating a two column bar graph. Means for each day I am showing the number of downloads and number of signups. Now I need to have a drilldown, which shows up the hourly data. The Highcharts docs is showing an example for Signle column by specifying the y value. But as I am showing stached bar, I have two y values for the same date. The code I am using is as follows :
series: [{
name : 'Signups,
color : '#0066FF',
data : <?=$series_1?>, //data in JSON format from PHP
drilldown: true
}, {
name : 'Downloads',
color : '#E81531',
data : <?=$series_2?>, //data in JSON format from PHP
drilldown: true
}],

Answer 1

Example for you for drilldown with two series, with stacking: 'normal': http://jsfiddle.net/6zYmJ/10/
$('#container').highcharts({
chart: {
type: 'column'
},
title: {
text: 'Basic drilldown'
},
xAxis: {
type: 'category'
},
legend: {
enabled: false
},
plotOptions: {
series: {
stacking: 'normal',
borderWidth: 0,
dataLabels: {
enabled: true,
}
}
},
series: [{
name: 'Things',
colorByPoint: true,
data: [{
name: 'Animals',
y: 5,
drilldown: 'animals'
}, {
name: 'Fruits',
y: 2,
drilldown: 'fruits'
}, {
name: 'Cars',
y: 4,
drilldown: 'cars'
}]
}, {
name: 'Things2',
colorByPoint: true,
data: [{
name: 'Animals2',
y: 5,
drilldown: 'animals2'
}, {
name: 'Fruits2',
y: 2,
drilldown: 'fruits2'
}, {
name: 'Cars2',
y: 4,
drilldown: 'cars2'
}]
}],
drilldown: {
series: [{
id: 'animals',
data: [
['Cats', 4],
['Dogs', 2],
['Cows', 1],
['Sheep', 2],
['Pigs', 1]
]
}, {
id: 'fruits',
data: [
['Apples', 4],
['Oranges', 2]
]
}, {
id: 'cars',
data: [
['Toyota', 4],
['Opel', 2],
['Volkswagen', 2]
]
},{
id: 'animals2',
data: [
['Cats', 4],
['Dogs', 2],
['Cows', 1],
['Sheep', 2],
['Pigs', 1]
]
}, {
id: 'fruits2',
data: [
['Apples', 4],
['Oranges', 2]
]
}, {
id: 'cars2',
data: [
['Toyota', 4],
['Opel', 2],
['Volkswagen', 2]
]
}]
}
})

Answer 2

Adding to Pawel Response-
Just replace in plotOptions with this value
column: {
pointPadding: 0.2,
borderWidth: 0
}
,