Question

我有 2 个表，第一个表名为 Activations，有两列：Line_ID、Activation_Date。第二个名为 Speed 的表具有以下列：Line_ID、From_Date、To_Date、Record。

第一个表格示例：

|Line_ID| Activation_Date|
|-------+----------------|
|123456 | 1-Jan          |
|345678 | 2-Jan          |
|987654 | 3-Jan          |
...

第二个间隙和岛屿表：

|Line_ID|From_Date| To_Date |Speed|
|-------+---------+---------+-----|  
|123456 |1-Jan    |4-Jan    |70   |
|123456 |4-Jan    |7-Jan    |51   |
|123456 |7-Jan    |10-Jan   |48   |
|123456 |10-Jan   |15-Jan   |40   |
|123456 |15-Jan   |17-Jan   |70   |
|123456 |17-Jan   |19-Jan   |54   |
|123456 |19-Jan   |21-Jan   |94   |
|123456 |21-Jan   |28-Jan   |91   |
|123456 |28-Jan   |31-Jan   |35   |
...

我需要将 Activation 表与 Records 表连接起来，以将 4 列添加到 Activation 表中，但有一些顾虑，

第一个：从 Activation_Date 开始的前 7 天记录的平均速度。
第二个：记录的第二个 7 天的平均速度。
3ed：记录从 Activation_Date 开始的第三个 7 天的平均速度。
第 4 天：记录从 Activation_Date 开始的第四个 7 天的平均速度。

结果如下

|Line_ID| Activation_Date|AVG_SPEED_Week1|AVG_SPEED_Week2|AVG_SPEED_Week3|AVG_SPEED_Week4|
|-------+----------------+---------------+---------------+---------------+---------------|
|123456 | 1-Jan          |60.5           |44             |72.6           |91             |
...

结果探索

AVG_SPEED_Week1: Average of Speed in the 1st 7 days starting Records.From_Date: 1-Jan Records.To_Date: 7-Jan
AVG_SPEED_Week2: Average of Speed in the 2nd 7 days starting Records.From_Date: 8-Jan Records.To_Date: 14-Jan
AVG_SPEED_Week3: Average of Speed in the 2nd 7 days starting Records.From_Date: 15-Jan Records.To_Date: 21-Jan
AVG_SPEED_Week4: Average of Speed in the 2nd 7 days starting Records.From_Date: 22-Jan Records.To_Date: 28-Jan

Answer 1

我无法测试它，但怎么样？：

SELECT a.Line_ID
,a.Activation_Date 
,CASE WHEN a.Activation_Date >= s.From_Date AND a.Activation_Date <= s.To_Date AND DATEADD(day,-7,s.To_Date) >= a.Activation_Date THEN AVG(SUM(s.Speed)) END AVG_SPEED_Week1
,CASE WHEN a.Activation_Date >= s.From_Date AND a.Activation_Date <= s.To_Date AND DATEADD(day,-14,s.To_Date) >= a.Activation_Date AND DATEADD(day,-7,s.From_Date) >= a.Activation_Date THEN AVG(SUM(s.Speed)) END AVG_SPEED_Week2
,CASE WHEN a.Activation_Date >= s.From_Date AND a.Activation_Date <= s.To_Date AND DATEADD(day,-21,s.To_Date) >= a.Activation_Date AND DATEADD(day,-14,s.From_Date) >= a.Activation_Date THEN AVG(SUM(s.Speed)) END AVG_SPEED_Week3
,CASE WHEN a.Activation_Date >= s.From_Date AND a.Activation_Date <= s.To_Date AND DATEADD(day,-28,s.To_Date) >= a.Activation_Date AND DATEADD(day,-21,s.From_Date) >= a.Activation_Date THEN AVG(SUM(s.Speed)) END AVG_SPEED_Week4
FROM Activations a
JOIN Speed s 
ON a.Line_ID=s.Line_ID
GROUP BY a.Line_ID, a.Activation_Date

我假设您不需要动态计算和生成任意周数的平均速度，4 周就足够了。

它肯定需要测试。

Answer 2

我会扩展数据并汇总：

with s as (
      select s.*, s.from_date + n.idx * interval '1 day' as dte
      from speed s join
           _V_VECTOR_IDX n
           on s.to_date <= s.from_date + n.idx * interval '1 day'
     )
select a.line_id,
       avg(case when s.dte between a.activation_date and a.activation_date + interval '6 day' then s.speed end),
       avg(case when s.dte between a.activation_date  + interval '7 day' and a.activation_date + interval '13 day' then s.speed end),
       avg(case when s.dte between a.activation_date  + interval '14 day' and a.activation_date + interval '20 day' then s.speed end),
       avg(case when s.dte between a.activation_date + interval '21 day' and a.activation_date + interval '27 day' then s.speed end)
from activations a left join
     s
     on a.line_id = s.line_id
group by a.line_id, a.activation_date;

这假设时间段少于 1000 天左右。

选择 2 个日期之间记录的平均值 SQL Netezza

2 个答案: