The following example shows how you can change the barWidthRatio style to control how wide each bar is in relation to the category width.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?> <!-- http://blog.flexexamples.com/2007/10/15/changing-the-bar-width-ratio-on-a-flex-bar-chart/ --> <mx:Application name="BarChart_barWidthRatio_test" xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalAlign="middle" backgroundColor="white"> <mx:ArrayCollection id="arrColl"> <mx:source> <mx:Array> <mx:Object name="R Winn" obp=".353" slg=".445" avg=".300" /> <mx:Object name="P Feliz" obp=".290" slg=".418" avg=".253" /> <mx:Object name="O Vizquel" obp=".305" slg=".316" avg=".246" /> <mx:Object name="B Molina" obp=".298" slg=".433" avg=".276" /> <mx:Object name="R Durham" obp=".295" slg=".343" avg=".218" /> </mx:Array> </mx:source> </mx:ArrayCollection> <mx:ApplicationControlBar dock="true"> <mx:Form> <mx:FormItem label="barWidthRatio:"> <mx:HSlider id="slider" minimum="0.0" maximum="1.0" value="0.6" liveDragging="true" tickInterval="0.1" /> </mx:FormItem> </mx:Form> </mx:ApplicationControlBar> <mx:BarChart id="barChart" showDataTips="true" dataProvider="{arrColl}" width="100%" height="100%"> <mx:verticalAxis> <mx:CategoryAxis categoryField="name"/> </mx:verticalAxis> <mx:series> <mx:BarSeries id="barSeries" yField="name" xField="avg" displayName="avg" barWidthRatio="{slider.value}" /> </mx:series> </mx:BarChart> </mx:Application>
View source is enabled in the following example.

{ 4 comments… read them below or add one }
Do you know if it’s possible to set the bar widths individually? Or change the spacing between bars individually?
@Rob,
I’m not aware of any, but I’m far from a Charting expert. You may want to ask on FlexCoders.
Peter
do you know how to display the data in a database on the barchart?
@angryProgrammer,
I think the easiest way would be to create a server-side script page using ColdFusion/PHP/ASP which retrieves the data from a database and outputs it as XML. Next, use the <mx:HTTPService/> tag in your Flex application to get the XML data from your server-side script and convert it into an XMLListCollection object which you can use as the BarChart control’s data provider.
Peter