如何将两个查询结果显示为一个答案

【问题标题】：How to display two queries results to one如何将两个查询结果显示为一个
【发布时间】：2017-08-11 09:28:54
【问题描述】：

我有两个 mysql 查询，它们为相同类型的列提供了不同的数据。现在我想将这两个结果合并为一个。以下是我的疑问。

查询-1：

SELECT cl.cand_corp_id as corpId, cl.shortlisted_timestamp as updatedDate, count(1) as activityCount
FROM candidates_log cl
where cl.shortlisted_timestamp > DATE_ADD(current_date(), INTERVAL -30 DAY)
group by cl.cand_corp_id
order by cl.shortlisted_timestamp desc

结果 1：

查询-2：

select j.corp_id as corpId, j.created_at as updatedDate, count(1) as activityCount
from jobs j
where j.created_at > DATE_ADD(current_date(), INTERVAL -30 DAY)
group by j.corp_id
order by activityCount, j.created_at desc limit 5

结果-2；

如何通过这两个结果集的并集得到最终结果。

【问题讨论】：

显示你需要的结果。如果两个结果集中都存在同一对 corpId, updatedDate，您需要对 activityCount 求和还是什么？

标签： mysql sql join merge

【解决方案1】：

您可以尝试 UNION ALL（应该在这两个查询之间）。如果列/数据的类型相同，它应该可以工作。

SELECT cl.cand_corp_id as corpId, cl.shortlisted_timestamp as updatedDate, count(1) as activityCount
FROM candidates_log cl
WHERE cl.shortlisted_timestamp > DATE_ADD(current_date(), INTERVAL -30 DAY)
GROUP BY cl.cand_corp_id
ORDER BY cl.shortlisted_timestamp desc
UNION ALL
SELECT j.corp_id as corpId, j.created_at as updatedDate, count(1) as activityCount
FROM jobs j
WHERE j.created_at > DATE_ADD(current_date(), INTERVAL -30 DAY)
GROUP BY j.corp_id
ORDER BY activityCount, j.created_at desc limit 5;

【讨论】：

【解决方案2】：

你可以使用 UNION ALL

select * from (
You could use union all  
SELECT cl.cand_corp_id as corpId, cl.shortlisted_timestamp as updatedDate, count(1) as activityCount
FROM candidates_log cl
where cl.shortlisted_timestamp > DATE_ADD(current_date(), INTERVAL -30 DAY)
group by cl.cand_corp_id
order by cl.shortlisted_timestamp desc
) t1

Union ALL 

select * from ( 
select j.corp_id as corpId, j.created_at as updatedDate, count(1) as activityCount
from jobs j
where j.created_at > DATE_ADD(current_date(), INTERVAL -30 DAY)
group by j.corp_id
order by activityCount, j.created_at desc limit 5
) t2
order by activityCount, updatedDate

【讨论】：

【解决方案3】：

Use UNION ALL Statement :

( SELECT cl.cand_corp_id as corpId, cl.shortlisted_timestamp as updatedDate,    
  count(1) as activityCount
  FROM candidates_log cl
  where cl.shortlisted_timestamp > DATE_ADD(current_date(), INTERVAL -30 DAY)
  group by cl.cand_corp_id
  order by cl.shortlisted_timestamp desc

)
UNION ALL
(
   select j.corp_id as corpId, j.created_at as updatedDate, count(1) as  
   activityCount
   from jobs j
   where j.created_at > DATE_ADD(current_date(), INTERVAL -30 DAY)
   group by j.corp_id
) 
ORDER BY updatedDate LIMIT 5

【讨论】：