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MYSQL(在某些条件下为SELECT)

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我是MYSQL初学者,但查询有问题：

我有两个表(calls,callsfailed).

>调用具有这些列(称为“ _number”,“ duration”).
> callfailed有这些列(称为_number,release_reason)

可以说通话表是：

+---------------+----------+
| called_number | duration |
+---------------+----------+
| 1010101       | 13       |
| 1010101       | 18       |
| 1010101       | 20       |
| 2020202       | 50       |
| 2020202       | 20       |
| 3030303       | 10       |
| 4040404       | 30       |
+---------------+----------+

失败呼叫表为：

+---------------+----------------+
| called_number | release_reason |
+---------------+----------------+
| 1010101       | -1             |
| 1010101       | -1             |
| 2020202       | -1             |
| 3030303       | 406            |
| 4040404       | 503            |
| 5050505       | -1             |
| 5050505       | -1             |
| 6060606       | -1             |
+---------------+----------------+

我想选择被叫号码> 1,当持续时间小于25时,或使release_reason = -1.超过1次.

BUT If the caller_number made a duration more than 25, don’t select it even when it has a release_reason = -1.

因此结果将是：

+---------------+-------+
| called_number | count |
+---------------+-------+
| 1010101       | 3     |
| 5050505       | 2     |
+---------------+-------+

我的代码是：

(  SELECT called_number, duration, COUNT(*) count 
   FROM calls 
   GROUP BY called_number 
   Having COUNT(called_number) > 1 and duration < 25 
) 

UNION 

( SELECT called_number, release_reason, COUNT(*) count 
  FROM callsfailed 
  GROUP BY called_number 
  Having COUNT(called_number) > 1 and release_reason = -1 
)

解决方法:

您可以使用UNION作为派生表,并在上面进行选择

SELECT t1.called_number, t1.count_calls FROM
(
    SELECT called_number, MAX(duration) max_duration, COUNT(called_number) count_calls 
    FROM calls 
    GROUP BY called_number 
    HAVING COUNT(called_number) > 1 AND max_duration < 25     

    UNION    

    SELECT called_number, release_reason, COUNT(called_number) count_callsfailed 
    FROM callsfailed 
    GROUP BY called_number 
    HAVING COUNT(called_number) > 1 AND release_reason = -1
) t1

GROUP BY t1.called_number

你有你的结果

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