Bar and Column Charts are one of the most common ways to visualize data. Both of these data visuals use rectangular bars where the size of the bar is proportional to the data values.
Column and bar charts let you compare different categories or track changes over time. What is the difference? If the rectangles are stacked horizontal, it's called a bar charts. If they are vertically aligned like towers, it's called a column chart (see fig 1-a above).
If the dimension on the x-axis is not a date and the names of the categories are long, it might be best to go with a bar chart rather than a column chart.
This is a pretty standard column chart showing sales data over a two year period. It is recommended to seperate the two years with a different color when comparing sales between two given years, with the previous year being a lighter shade. While you can hover over each bar to compare sales, it would be nice to have a better side by side comparison to see which months did better or worse.
A clustered column charts is essentially a column chart that lets you compare two values side by side. In this case we are comparing sales for each month over a period of two years. Hovering over one of the values lets you see the % difference between the selected month and the sales values. A stacked column chart is very similar except the bars for each month will be stacked on top of each other rather then side by side. It is now easy to compare sales data last year vs this year for each month. For this sample data, October was the only month sales were down compare to last year.