Data column(s) for axis #0 cannot be of type string error in google chart

Question

I tried to populate google chart datatable in server side using PHP.I got JSON file properply, but the Chart not display in client Application. I got error-Data colu

Answer 1

You specify type of userid as number... but pass string.. thats causing the problem.

I just wasted 30 mins with the opposite problem ...

Your output json should look like :-

{
  "cols":[
    {"id":"","label":"userid","pattern":"","type":"number"},
    {"id":"","label":"name","pattern":"","type":"string"}
   ],
  "rows":[
    {"c":[{"v":101},{"v":"Aircel"}]},
    {"c":[{"v":102},{"v":"Srini"}]},
    {"c":[{"v":103},{"v":"Tamil"}]},
    {"c":[{"v":104},{"v":"Thiyagu"}]},
    {"c":[{"v":105},{"v":"Vasan"}]},
    {"c":[{"v":107},{"v":"Senthil"}]},
    {"c":[{"v":108},{"v":"Sri"}]},
    {"c":[{"v":109},{"v":"Docomo"}]},
    {"c":[{"v":106},{"v":"Innodea"}]}
    ]
}

Answer 2

If the Data format should be like:

data: [
    ["string", "string"], //first Column
    ["string1", number],
    ["string2", number],
    ["string3", number],
]

then you can overcome this error.

Answer 3

To extend on @sajal's accurate answer: Change the last line of your code from:

echo json_encode($table);

to:

echo json_encode($table, JSON_NUMERIC_CHECK);

This will tell json_encode to recognize numbers and abstain from wrapping them in quotes (Available since PHP 5.3.3.). http://php.net/manual/en/json.constants.php#constant.json-numeric-check

Answer 4

In your drawChart() function, you are probably using google.visualization.arrayToDataTable, and this does not allow any nulls. Please use addColumn function explicitly

Answer 5

On a BarChart, one of the columns (the second one) has to be a number. That can cause this error message.