Question

在一个带有行的表中介绍狗的交配。通常在母体热循环中发生多次交配，因此，具有相同母体且加热时间紧密的交配意味着单个热循环。例如：

Date         Female
----------   ---------
2019-03-28   Female1
2019-04-01   Female1
2019-04-03   Female1
2019-10-15   Female2
2019-10-16   Female2
2019-10-19   Female1
2019-10-23   Female1

在表中，您可以看到三个交配组，其中2个代表雌性1，1个代表雌性2。我想选择这些行，然后在结果中添加一列，以标识不同分组的配对关系。分组中的开始日期和结束日期相隔不超过10天。

我尝试将日期字段转换为纪元秒，然后除以某个数字。这给了我一些东西，但是分组中有很多错误。

Answer 1

WITH cte AS (
SELECT "Date",
       "Female",
-- assume that the lag is not more than 7 days
       CASE WHEN ("Date" - LAG("Date") OVER (PARTITION BY "Female" ORDER BY "Date")) <= 7
            THEN 0
            ELSE 1 END "is it mating start?"
FROM matings
)
SELECT "Date",
       "Female",
       SUM("is it mating start?") OVER (PARTITION BY "Female" ORDER BY "Date") "mating number"
FROM cte
ORDER BY "Female", "Date";

fiddle

如何按日期分组在一起？

1 个答案: