如何使SQL查询获取特定列的总和? [英] How to make SQL Query to get the sum of specific column?

问题描述

以前，我使用Ajax绘制了一个Google图表(饼图)，该图表可以显示，因为它仅涉及2列.

Previously I draw a google chart (Pie Chart), using Ajax and the chart can be displayed as it only involved 2 columns.

现在，我想绘制一个像这样的柱状图.

Now, I want to draw a column chart like this one.

这是我的SQL查询:

$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";

使用以下代码将查询编码到Json输出中:

The query is coded into Json output using this:

$result_rows = mysql_num_rows($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['category_group'] . "\",\"f\":null},{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]},";
} else {
   echo "{\"c\":[{\"v\":\"" . $result['category_group'] . "\",\"f\":null},{\"v\":\"" . $result['application_status'] . "\",\"f\":null},{\"v\":" . $result['count'] . ",\"f\":null}]},";
}
}


echo " ] }";

这是输出:

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

但是，由于应用程序状态的值不是数字，因此图表无法正确显示.我确实阅读了其他解决方案，以通过sql中的sum函数获得结果，但是我不知道该怎么做.

However, the chart don't display correctly because the value of application status is not a number. I do read on the other solutions to get the result by sum function in sql but I do not know how to do it.

我的问题:我想如何执行SQL查询以获取每个应用程序状态(0,1,2--状态类型)的总数

My question: How I want to do SQL Query to get the total count of each application status (0,1,2--status type)

我的预期输出是这样的:

My expected output is to be like this:

{ "cols": [ {"id":"","label":"CATEOGRY","pattern":"","type":"string"}, {"id":"","label":"CATEOGRY","pattern":"","type":"number"}, {"id":"","label":"TOTAL","pattern":"","type":"number"} ], "rows": [ {"c":[{"v":"Accounting/Finance","f":null},{"v":4,"f":null},{"v":2,"f":null}]},{"c":[{"v":"Engineering","f":null},{"v":7,"f":null},{"v":1,"f":null}]}, ] }  

区别在于第二个数组值，我想通过执行SQL查询(使用sum函数)来获取该值，以获取状态为0状态，1状态和2状态的每个状态的计算总和.

The difference is in the second array value, I want to have the value by making SQL Query (using sum function) to get calculated sum for each status that are 0 status, 1 status, and 2 status.

{"c":[{"v":"Accounting/Finance","f":null},{"v":4,"f":null},{"v":2,"f":null}]},

如果我执行此查询(更改where语句，则只能获取状态"0"的计数.如何在同一查询中添加另一个where语句以获取其他状态的计数，即状态"1""和状态"2"?

If I make this Query(changes in where statement, I can only get the count of status "0" only. How I want to add another where statement in the same query to get the count of other status, status "1" and status "2"?

$sql = "Select count(application_id) as count, 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' and application_status = 0
 group by category_group";

推荐答案

我尝试了以下SQL查询:

I tried this SQL Query:

$sql = "Select count(application_id) as count, sum(case when application_status = 0 then 1 else 0 end) PendingCount, sum(case when application_status = 1 then 1 else 0 end) RejectedCount, sum(case when application_status = 2 then 1 else 0 end)SuccessCount, 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 category_group";

这是输出:

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

可以根据状态类型显示图表.

The chart can appear according to the status type..

无论如何，谢谢@ Alex，@ Oleg的评论和分享，以帮助我摆脱困境.很抱歉让您对我的问题感到困惑.

Anyway, thank you @Alex, @Oleg for your comment and sharing to get me out from the problem. I'm sorry for getting you into puzzle with my problem.

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