Question

我有一个具有以下结构的表： -

day,        id
2016-03-13, 123
2016-03-13, 123
2016-03-13, 231
2016-03-14, 231
2016-03-14, 231
2016-03-15, 129

我想构建一个看起来像这样的表： -

id,   d1, d7, d14
123,  1,  1,  1
231,  1,  2,  2
129,  1,  1,  1

基本上对于给定的ID，列出在时间窗口内具有条目的天数。因此，如果id 123在过去14天内有10个条目 - d14将为10。

到目前为止，我有： -

    SELECT
        day,
        id
    FROM
        events
    WHERE
        datediff (DAY, day, getdate()) <= 7
    GROUP BY
        day,
        id

Answer 1

此查询将执行：

SELECT
    id,
    COUNT(DISTINCT CASE WHEN current_date - day <=  1 THEN 1 END) d1,
    COUNT(DISTINCT CASE WHEN current_date - day <=  7 THEN 1 END) d7,
    COUNT(DISTINCT CASE WHEN current_date - day <= 14 THEN 1 END) d14
FROM
    events
GROUP BY
    id
ORDER BY
    id

或者，从PostgreSQL 9.4开始，稍微简洁一点：

SELECT
    id,
    COUNT(DISTINCT day) FILTER (WHERE current_date - day <=  1) d1,
    COUNT(DISTINCT day) FILTER (WHERE current_date - day <=  7) d7,
    COUNT(DISTINCT day) FILTER (WHERE current_date - day <= 14) d14
FROM
    events
GROUP BY
    id
ORDER BY
    id

Answer 2

试试这个：

SELECT id
, count(case when DAY = getdate() then 1 else null end) as d1
, count(case when DAY + 7 >= getdate() then 1 else null end) as d7
, count(case when DAY + 14 >= getdate() then 1 else null end) as d14
FROM events
WHERE DAY between DAY >= getdate() - 14 
--or if you can have day > today ...  and DAY between getdate() - 14 and getdate()
GROUP By id

日期之间的条目数

2 个答案: