如何重新格式化柱狀圖的json輸出？

Question

以前我使用Ajax繪製了一個谷歌圖表（餅圖），圖表可以顯示，因爲它只涉及2列。

現在，我想畫一個這樣的柱狀圖。

這是我的SQL查詢：

$sql = "Select count(application_id) as count, application_status, category_group from mdl_local_jobs_application 
inner join mdl_local_jobs_job on mdl_local_jobs_application.application_jobid = mdl_local_jobs_job.job_id 
left join mdl_local_jobs_category on mdl_local_jobs_job.job_categoryid = mdl_local_jobs_category.category_id 
left join mdl_cohort_members on mdl_local_jobs_application.application_applicantid = mdl_cohort_members.userid 
left join mdl_local_cohortrole on mdl_cohort_members.cohortid = mdl_local_cohortrole.cohortid 
left join mdl_role on mdl_local_cohortrole.roleid = mdl_role.id where shortname = 'graduates' 
group by application_status, category_group"; 

查詢被編碼成JSON輸出使用此：

$result_rows = mysql_num_rows($query); 
$row_num = 0; 

//loop fetching the query into json format 
while ($result = mysql_fetch_array($query)) 
{ 
$row_num++; 
if ($row_num == $result_rows){ 
    echo "{\"c\":[{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":\"" . $result['category_group'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]}"; 
} else { 
    echo "{\"c\":[{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":\"" . $result['category_group'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]}"; 
} 
} 


echo " ] }"; 

這是輸出：

{ "cols": [ {"id":"","label":"STATUS","pattern":"","type":"string"}, {"id":"","label":"CATEOGRY","pattern":"","type":"string"}, {"id":"","label":"TOTAL","pattern":"","type":"number"} ], "rows": [ {"c":[{"v":"0","f":null},{"v":"Accounting/Finance","f":null},{"v":2,"f":null}]}{"c":[{"v":"0","f":null},{"v":"Engineering","f":null},{"v":1,"f":null}]} ] } 

但是，谷歌圖表無法讀取此輸出。這是錯誤。

Error: Invalid JSON string: { "cols": [ {"id":"","label":"STATUS","pattern":"","type":"string"}, {"id":"","label":"CATEOGRY","pattern":"","type":"string"}, {"id":"","label":"TOTAL","pattern":"","type":"number"} ], "rows": [ {"c":[{"v":"0","f":null},{"v":"Accounting/Finance","f":null},{"v":2,"f":null}]}{"c":[{"v":"0","f":null},{"v":"Engineering","f":null},{"v":1,"f":null}]} ] } 

我的問題：我如何重新格式化代碼以獲得列圖的輸出？

Answer 1

需要一個逗號添加到每一行的結尾......

if ($row_num == $result_rows){ 
    echo "{\"c\":[{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":\"" . $result['category_group'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]},"; // <-- add comma 
} else { 
    echo "{\"c\":[{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":\"" . $result['category_group'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]},"; // <-- add comma 
}