Question

我有下表：

id | whenCreated    | callingNumber |
---|--------------------------------|
1  | 1-1-2016 9:00  | 0612345678    |
2  | 1-1-2016 9:10  | 0623456789    |
3  | 1-1-2016 9:55  | 0612345678    |
4  | 1-1-2016 10:15 | 0623456789    |
5  | 1-1-2016 11:00 | 0623456789    |
etc.

Datatypes:
id = int (AI)
whenCreated = datetime
callingNumber = varchar

我想分析一下有多少人在他们之前的通话后的一段时间内回电（例如，假设1小时）。为此，我想找一个人在之前一段时间之前打过电话的次数。在这个例子中，结果应该是这样的：

id | whenCreated    | callingNumber | prevCalls |
---|--------------------------------|-----------|
1  | 1-1-2016 9:00  | 0612345678    | 0         | < 0, because no previous calls
2  | 1-1-2016 9:10  | 0623456789    | 0         | < 0, because no previous calls
3  | 1-1-2016 9:55  | 0612345678    | 1         | < 1, because one call from this number in the last hour
4  | 1-1-2016 10:15 | 0623456789    | 0         | < 0, there was one earlier call from this number, but it was more than an hour ago
5  | 1-1-2016 11:00 | 0623456789    | 1         | < 1, because one call from this number in the last hour
etc.

有什么方法可以用MySQL中的一个查询来做到这一点吗？或者我必须为此运行脚本？（我知道如何单独为每一行做这件事，我似乎无法通过一个查询找到一种方法）。

Answer 1

您可以使用相关子查询来执行此操作：

SELECT id, whenCreated, callingNumber,
       (SELECT COUNT(*)
        FROM mytable AS t2
        WHERE t2.callingNumber = t1.callingNumber AND
              t2.id < t1.id AND 
              TIMESTAMPDIFF(MINUTE, t2.whenCreated, t1.whenCreated) < 60)
FROM mytable AS t1

该查询使用TIMESTAMPDIFF来计算两个whenCreated值之间的差异。

Demo here

如何在两个变量日期之间找到重复项

1 个答案: