You can find a lot of examples on how to build PocketQuery templates with Google Charts on the page Google Charts Examples.
Adding A Chart
The argument - "BarChart" in this case - specifies which type of chart you want to render. As default, the result of the corresponding query will be used as the data set for the chart.
Which charts are available?
Overriding the Data Table for Google Charts
PocketQuery uses the query result for the data table used in Google Charts. You can override this data table with your own. Obviously, then the query result will have no effect on the resulting chart. The following example uses the Org Chart with the example data from the Google Charts docs: