在同一查询中具有不同条件的Postgres计数

编辑 Postgres 9.3

我正在处理具有以下架构的报告：http : //sqlfiddle.com/#!15/fd104/2

当前查询工作正常，如下所示：

基本上它是一个3表内部联接。我没有进行此查询，但是留下查询的开发人员想修改查询。如您所见，TotalApplication只计算基于的总申请量a.agent_id。您可以totalapplication在结果中看到该列。我要删除的是并将其更改totalapplication为新的两列。我想添加completedsurvey和partitalsurvey列。所以基本上这部分将成为

SELECT a.agent_id as agent_id, COUNT(a.id) as CompletedSurvey
FROM forms a WHERE  a.created_at >= '2015-08-01' AND 
a.created_at <= '2015-08-31' AND disposition = 'Completed Survey'
GROUP BY a.agent_id

我刚刚添加了，AND disposition = 'Completed Survey'但是我需要另一列partialsurvey具有相同查询的列，completedsurvey唯一的区别是

AND disposition = 'Partial Survey'

和

COUNT(a.id) as PartialSurvey

但是我不知道将查询放在哪里或查询的样子，所以最终输出包含这些列

agent_id, name, completedsurvey, partialsurvey, loginhours, applicationperhour, rph

一切正常之后，可以申请每小时和RPH，我可以自己修复

如果我对您的理解正确，那么您正在寻找经过过滤的（有条件的）集合：

SELECT a.agent_id as agent_id, 
       COUNT(a.id) filter (where disposition = 'Completed Survey') as CompletedSurvey, 
       count(a.id) filter (where disposition = 'Partial Survey') as partial_survey
FROM forms a 
WHERE a.created_at >= '2015-08-01' 
  AND a.created_at <= '2015-08-31' 
GROUP BY a.agent_id;

对于旧版本（<9.4）进行编辑，您需要使用以下case语句：

SELECT a.agent_id as agent_id, 
       COUNT(case when disposition = 'Completed Survey' then a.id end) as CompletedSurvey, 
       COUNT(case when disposition = 'Partial Survey' then a.id end) as partial_survey
FROM forms a 
WHERE a.created_at >= '2015-08-01' 
  AND a.created_at <= '2015-08-31' 
GROUP BY a.agent_id;