Question

我希望有人可以在这里查看我的语法。我有一个用户表subscribers和一个事件表text_alert。

我希望在2017-07-07之前和之后分配发送给每个用户的文字提醒总数。

这是我的疑问：

  select
    subs.id as subscriber_id,
    count(t.id) as total_alerts_received,
    count(tbefore.id) as before_alerts_received,
    count(tafter.id) as after_alerts_received
  from subscriber subs
  left join text_alert t on t.subscriber_id = subs.id
  left join text_alert tbefore on tbefore.subscriber_id = subs.id and tbefore.create_date_time::date <= '2017-07-07'
  left join text_alert tafter on tafter.subscriber_id = subs.id and tafter.create_date_time::date > '2017-07-07'
  where subs.sms = 0
  group by subs.id

我的期望是alerts_received字段之前和之后的总和与total_alerts_received匹配。而发生的是3个字段具有相同的值。如果订阅者010有十个警报，则字段之前和之后也会有10个警报。

要在事实表警告上使用左连接之前和之后拆分。

任何帮助都非常感激。

Answer 1

ChildComponent

Answer 2

SELECT 
    subscriberId, 
    beforeAlerts, 
    afterAlerts, 
    beforeAlerts + afterAlerts as totalAlerts
FROM (
    SELECT 
        DISTINCT subs.id as subscriberId, 
        (SELECT COUNT(*) FROM text_alert tb WHERE
            tb.subscriber_id = subs.id AND
            tb.create_date_time <= '2017-07-07') as beforeAlerts, 
        (SELECT COUNT(*) FROM text_alert ta WHERE
            ta.subscriber_id = subs.id AND
            ta.create_date_time > '2017-07-07') as afterAlerts
    FROM subscriber subs
) AS results;

试图在截止日期之前和之后分割事件的数量

2 个答案: