Question

我已尝试过以下查询，但遗憾的是他们没有工作:(。值得一提的是每个客户都有多个CustomerUsers

select (a.TotalJobs / b.DaysActive) from
(select count(jr.id) as TotalJobs
from jobrequests jr, customers c, customerusers cu
where jr.customeruserid=cu.id
and cu.customerid=c.id
group by c.name) as a,
(select datediff(curdate(), from_unixtime(c.CreationTime)) as DaysActive
from customers c
group by c.name)  as b

请参见下表

 
Jobs:                  
 +----+--------------+
| ID | JobRequestID |
+----+--------------+
|  1 |            1 | 
|  2 |            1 |
|  3 |            1 |
|  4 |            1 |
|  5 |            1 |
|  6 |            2 |
|  7 |            2 |
|  8 |            3 |
|  9 |            3 |
| 10 |            3 |
| 11 |            4 |
| 12 |            4 |
| 13 |            5 |
| 14 |            5 |
| 15 |            6 |
| 16 |            7 |
| 17 |            8 |
| 18 |            8 |
| 19 |            9 |
| 20 |           10 |
+----+--------------+  
JobRequests:
+----+---------------+
| ID | CustomeUserID |
+----+---------------+
|  1 |             1 |
|  2 |             1 |
|  3 |             2 |
|  4 |             2 |
|  5 |             2 |
|  6 |             3 |
|  7 |             4 |
|  8 |             4 |
|  9 |             4 |
| 10 |             5 |
| 11 |             5 |
| 12 |             5 |
| 13 |             6 |
| 14 |             6 |
| 15 |             7 |
+----+---------------+        

CustomerUsers:
+----+------------+
| ID | CustomerID |
+----+------------+
|  1 |          1 |
|  2 |          1 |
|  3 |          1 |
|  4 |          2 |
|  5 |          2 |
|  6 |          2 |
|  7 |          2 |
|  8 |          3 |
|  9 |          3 |
| 10 |          4 |
+----+------------+

Customers:
+----+------+--------------+
| ID | Name | CreationTime |
+----+------+--------------+
|  1 | a    |   1415814194 |
|  2 | b    |   1415814194 |
|  3 | c    |   1415986994 |
|  4 | d    |   1415986994 |
+----+------+--------------+

目前它返回16个结果（4X4），将每个结果从第一个子查询除以第二个每个结果（每个子查询返回4个结果）。任何人都可以帮我解决这个问题，将子查询1的1个结果除以子查询2中的对应者吗？

提前谢谢。

Answer 1

我怀疑你可以做这样的查询：

select c.name, count(*) / (datediff(curdate(), from_unixtime(c.CreationTime))
from customerusers cu join
     jobrequests jr
     on jr.customeruserid = cu.id join
     customers c 
     on cu.customerid = c.id
group by c.name;

我不明白为什么你需要两个子查询。

Answer 2

我猜你需要join你的结果 - 正如目前所写，你正在制作一个cartesian product。

尝试这样的方法将c.id添加到每个子查询中（最好将其按名称分组，而不是名称）：

select (a.TotalJobs / b.DaysActive) 
from (
     select c.id, 
            count(jr.id) as TotalJobs
     from jobrequests jr   
          join customers c on jr.customeruserid=cu.id
          join customerusers cu on cu.customerid=c.id
     group by c.id) a join (
          select c.id, 
                 datediff(curdate(), from_unixtime(c.CreationTime)) as DaysActive
          from customers c
          group by c.id) b on a.id = b.id

请注意，我已更新您的语法以使用更标准的join语法。

MySQL如何查找具有不同创建日期的不同客户的平均值/天

2 个答案: