Google charts JSON format for stacked bar chart

Question

EDIT: I am looking for an example in the layout below. I may be missing something as this is my first time with Google Charts... Thanks for the help!

{
  "cols": [
        {"id":"","label":"Store 1","pattern":"","type":"number"},
        {"id":"","label":"Store 2","pattern":"","type":"number"},
        {"id":"","label":"Store 3","pattern":"","type":"number"},...
      ],
  "rows": [
        {"c":[{"v":"morning","f":'15'},{"v":"noon","f":'20'},{"v":"night","f":'25'}]},...
      ]
}

I cannot find anywhere an example of how the JSON record needs to be formatted for a stacked bar chart for Google Charts. I have tried a few combinations but I am struggling visualising it.

My data contains:

           Store 1   Store 2
store_id   walk-ins  walk-ins
morning      20        25
noon         35        40
night        50        55

There are 20 stores to chart stacking the values of each row.

My JSON right now looks like:

[{"store_id":"Store 1","time":"morning","walk-ins":"20"}, and so on...]

I am happy to share the PHP once I work out what it needs to format the record like! Can someone point me to an example that may exist that I have missed please. Thanks for any help.

Answer 1

Have you checked the Documentation ?

The JSON format seems to be an array of arrays :

 var data = google.visualization.arrayToDataTable([
          ['Year', 'Sales', 'Expenses'],
          ['2004',  1000,      400],
          ['2005',  1170,      460],
          ['2006',  660,       1120],
          ['2007',  1030,      540]
        ]);

that means your data would look like this:

[
    ["store_id", "time","walk-ins"],
    ["Store 1","morning","30"],
    ["Store 2","afternoon","40"],
    ["Store 3","night","50"]
]