Question

我有一张表格，列出了人们的问题（又名任务），我想算出有多少被标记为“准时关闭”。

说实话，我对SQL查询的经验还不是很丰富，我正试图仅按月提取所有已关闭任务的数据。

以下是（postgres）SQL查询：

SELECT
    cast(date_trunc('month', b.closed_on) as date) AS time,
    count(distinct a.issue_id) as "Tasks Closed On Time"
from redmine_issues_summary a
left join redmine_issues_summary b on cast(date_trunc('month', b.closed_on) as date) = cast(date_trunc('month', a.closed_on) as date)
WHERE
  a.assignee_groups in('Modelling','Global') and
  a.tracker in('Administration','Costing','N.A.','Prototype Shop','Simulation') and 
  a.closed_on_time = 'On Time'
group by cast(date_trunc('month', b.closed_on) as date)
ORDER BY cast(date_trunc('month', b.closed_on) as date)

但是，我在联接上做错了，因为我没有得到计数为零的行。

有人可以帮我吗？

编辑：

@Tim的回答帮助我找到了解决方案。

SELECT
    cast(date_trunc('month', b.closed_on) as date) AS time,
    SUM(case when a.closed_on_time = 'On Time' and a.assignee_groups in('LOH_Modelling&Analysis','LOH_Modelling&Analysis, Global_CAE','LOH_Modelling&Analysis, KOP_CAE, Global_CAE','Project_Admin, LOH_Modelling&Analysis','Project_Admin, LOH_Modelling&Analysis, Global_CAE') and
  a.top_parent_project_name in('1_Global GKN Projects') and 
  a.tracker in('Administration') THEN 1 ELSE 0 END) as "Tasks Closed On Time"
from redmine_issues_summary a
left join redmine_issues_summary b on cast(date_trunc('month', b.closed_on) as date) = cast(date_trunc('month', a.closed_on) as date)
group by cast(date_trunc('month', b.closed_on) as date)
ORDER BY cast(date_trunc('month', b.closed_on) as date)

Answer 1

尝试使用条件聚合：

SELECT
    cast(date_trunc('month', b.closed_on) as date) AS time,
    sum(case when a.closed_on_time = 'On Time' THEN 1 ELSE 0 END) as "Tasks Closed On Time"
from redmine_issues_summary a
left join redmine_issues_summary b
    on cast(date_trunc('month', b.closed_on) as date) = cast(date_trunc('month', a.closed_on) as date)
WHERE
    a.assignee_groups in('Modelling','Global') and
    a.tracker in('Administration','Costing','N.A.','Prototype Shop','Simulation')
group by
    cast(date_trunc('month', b.closed_on) as date)
ORDER BY
    cast(date_trunc('month', b.closed_on) as date)

这假定您不想包括不在指定的受让人或跟踪者组中的任何记录。如果您要做要包括这些记录，那么我的答案将需要更新。

Answer 2

在选择中使用左表，您在选择中使用了右表列（b.closed_on），则需要更改（a.closed_on）

SELECT
    cast(date_trunc('month', a.closed_on) as date) AS time,
    count(distinct a.issue_id) as "Tasks Closed On Time"
from redmine_issues_summary a
left join redmine_issues_summary b on cast(date_trunc('month', b.closed_on) as date) = cast(date_trunc('month', a.closed_on) as date)
WHERE
  a.assignee_groups in('Modelling','Global') and
  a.tracker in('Administration','Costing','N.A.','Prototype Shop','Simulation') and 
  a.closed_on_time = 'On Time'
group by cast(date_trunc('month', a.closed_on) as date)
ORDER BY cast(date_trunc('month', a.closed_on) as date)

在按日期分组的SQL查询中包括零

2 个答案: