在MySQL中合并多个查询结果(按列) [英] Combine Multiple Query Results in MySQL (by column)
问题描述
我有4个不同的查询,每个查询都返回一组唯一的结果. 我需要将查询结果与使用单个查询结合起来.
I have 4 different queries and each of them return individual unique set of Results. I need to combine the Query Results with using a single query.
我的示例查询是:
1. select cls.* from (calls as cls inner join calls_users as clsusr on cls.id=clsusr.call_id) inner join users as usr on usr.id=cls.assigned_user_id where cls.assigned_user_id='seed_max_id'
2. select mtn.* from (meetings as mtn inner join meetings_users as mtnusr on mtn.id=mtnusr.meeting_id) inner join users as usr on usr.id=mtn.assigned_user_id where mtn.assigned_user_id='seed_max_id'
3. select tsk.* from tasks as tsk inner join users as usr on usr.id=tsk.assigned_user_id where tsk.assigned_user_id='seed_max_id'
4. select nts.* from (notes as nts inner join accounts as acnts on acnts.id=nts.parent_id) inner join users as usr on usr.id=acnts.assigned_user_id where acnts.assigned_user_id='seed_max_id'
我尝试了以下方法,但是没有用
I tried the following way, but it didn't work
Combine: SELECT tbl1.*, tbl2.*
from (select cls.* from (calls as cls inner join calls_users as clsusr on cls.id=clsusr.call_id) inner join users as usr on usr.id=cls.assigned_user_id where cls.assigned_user_id='seed_max_id') as tbl1
left outer join
(select mtn.* from (meetings as mtn inner join meetings_users as mtnusr on mtn.id=mtnusr.meeting_id) inner join users as usr on usr.id=mtn.assigned_user_id where mtn.assigned_user_id='seed_max_id') as tbl2
using(assigned_user_id)
我还尝试了正确的外部联接和其他内部联接 我真的很困惑,如果有人知道解决方案,那么请帮忙. 我需要类似的结果,例如
i also tried right outer join and other inner joins I am really stuck, if any one know the solution then please help. I need the similar result like How can I join two tables with different number of rows in MySQL?.
数据样本:
从查询1:
+-------------------------------------------+------------------+-
| Call Name | Call Description |
+-------------------------------------------+------------------+-
| Discuss Review Process | NULL |
| Get More information on the proposed deal | NULL |
| Left a message | NULL |
| Discuss Review Process | NULL |
+-------------------------------------------+------------------+
从查询2:
+-----------------------+-----------------------------------------------------------
| Meeting Name | Meeting Description
+-----------------------+-----------------------------------------------------------
| Review needs | Meeting to discuss project plan and hash out the details o
| Initial discussion | Meeting to discuss project plan and hash out the details o
| Demo | Meeting to discuss project plan and hash out the details o
| Discuss pricing | Meeting to discuss project plan and hash out the details o
| Review needs | Meeting to discuss project plan and hash out the details o
+-----------------------+-----------------------------------------------------------
我需要合并以下列:
+-------------------------------------------+------------------+-------------------+-------------------+
| Call Name | Call Description |Meeting Name |Meeting Description|
+-------------------------------------------+------------------+-------------------+-------------------+
| Discuss Review Process | NULL |Review needs |Meeting to discuss |
| Get More information on the proposed deal | NULL |Initial discussion |Meeting to discuss |
| Left a message | NULL |Demo |Meeting to discuss |
| NULL | NULL |Discuss pricing |Meeting to discuss |
| NULL | NULL |Review needs |Meeting to discuss |
+-------------------------------------------+------------------+-------------------+-------------------+
推荐答案
您能做的最好的是UNION或UNION ALL,但这要求它们具有相同的类型和列数.例如:
The best you can do is a UNION or UNION ALL but this requires them to have the same type and number of columns. For example:
SELECT 'Customer' AS type, id, name FROM customer
UNION ALL
SELECT 'Supplier', id, name FROM supplier
UNION ALL
SELECT 'Employee', id, full_name FROM employee
列名不必匹配.第一部分的别名将用于其余部分.
The column names don't have to match. The aliases from the first part will be used for the rest.
我还将添加它,而不是:
I'll also add that instead of:
select cls.* from (calls as cls inner join calls_users as clsusr on cls.id=clsusr.call_id) inner join users as usr on usr.id=cls.assigned_user_id where cls.assigned_user_id='seed_max_id'
您应该删除不必要的子查询,然后执行以下操作:
you should remove the unnecessary subquery and just do:
SELECT c.*
FROM calls c
JOIN calls_users cu ONc.id = cu.call_id
WHERE c.assigned_user_id = 'seed_max_id'
不需要额外的复杂性,并且上面的内容明显更具可读性.
There's no need for the extra complexity and the above is eminently more readable.
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