上一期间分区上的SQL和
我有下表,代表每天的客户:上一期间分区上的SQL和,sql,teradata,Sql,Teradata,我有下表,代表每天的客户: +----------+-----------+ | Date | Customers | +----------+-----------+ | 1/1/2014 | 4 | | 1/2/2014 | 7 | | 1/3/2014 | 5 | | 1/4/2014 | 5 | | 1/5/2014 | 10 | | 2/1/2014 | 7 | | 2/2/2014
+----------+-----------+
| Date | Customers |
+----------+-----------+
| 1/1/2014 | 4 |
| 1/2/2014 | 7 |
| 1/3/2014 | 5 |
| 1/4/2014 | 5 |
| 1/5/2014 | 10 |
| 2/1/2014 | 7 |
| 2/2/2014 | 4 |
| 2/3/2014 | 1 |
| 2/4/2014 | 5 |
+----------+-----------+
我想再添加两列:
+----------+-----------+----------------------+------------------------+
| Date | Customers | Sum_of_Current_month | Sum_of_Preceding_month |
+----------+-----------+----------------------+------------------------+
| 1/1/2014 | 4 | 31 | 0 |
| 1/2/2014 | 7 | 31 | 0 |
| 1/3/2014 | 5 | 31 | 0 |
| 1/4/2014 | 5 | 31 | 0 |
| 1/5/2014 | 10 | 31 | 0 |
| 2/1/2014 | 7 | 17 | 31 |
| 2/2/2014 | 4 | 17 | 31 |
| 2/3/2014 | 1 | 17 | 31 |
| 2/4/2014 | 5 | 17 | 31 |
+----------+-----------+----------------------+------------------------+
我已经设法通过简单的分区函数求和来计算第三列:
Select
Date,
Customers,
Sum(Customers) over (Partition by (Month(Date)||year(Date) Order by 1) as Sum_of_Current_month
From table
但是,我找不到一种方法来计算前一个月列的和
感谢您的支持
Asaf我认为使用
lag()
和聚合子查询可能会更容易。ANSI标准语法为:
Select t.*, tt.sumCustomers, tt.prev_sumCustomers
From table t join
(select extract(year from date) as yyyy, extract(month from date) as mm,
sum(Customers) as sumCustomers,
lag(sum(Customers)) over (order by extract(year from date), extract(month from date)
) as prev_sumCustomers
from table t
group by extract(year from date), extract(month from date)
) tt
on extract(year from date) = tt.yyyy and extract(month from date) = t.mm;
在Teradata中,这可以写成:
Select t.*, tt.sumCustomers, tt.prev_sumCustomers
From table t join
(select extract(year from date) as yyyy, extract(month from date) as mm,
sum(Customers) as sumCustomers,
min(sum(Customers)) over (order by extract(year from date), extract(month from date)
rows between 1 preceding and 1 preceding
) as prev_sumCustomers
from table t
group by extract(year from date), extract(month from date)
) tt
on extract(year from date) = tt.yyyy and extract(month from date) = t.mm;
试试这个:
SELECT
[Date],
[Customers],
(SELECT SUM(customers) FROM table WHERE MONTH(dte) = MONTH(tbl.dte)),
ISNULL((SELECT SUM(customers) FROM table WHERE MONTH(dte) = MONTH(DATEADD(MONTH, -1, tbl.dte))), 0)
FROM table tbl
上个月有点棘手。您的Teradata版本是什么,TD14.10支持
LAST\u值
:
SELECT
dt,
customers,
Sum_of_Current_month,
-- return the previous sum
COALESCE(LAST_VALUE(x ignore NULLS)
OVER (ORDER BY dt
ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING)
,0) AS Sum_of_Preceding_month
FROM
(
SELECT
dt,
Customers,
SUM(Customers) OVER (PARTITION BY TRUNC(dt,'mon')) AS Sum_of_Current_month,
CASE -- keep the number only for the last day in month
WHEN ROW_NUMBER()
OVER (PARTITION BY TRUNC(dt,'mon')
ORDER BY dt)
= COUNT(*)
OVER (PARTITION BY TRUNC(dt,'mon'))
THEN Sum_of_Current_month
END AS x
FROM tab
) AS dt
在这种情况下,我希望有一个0的值。看看这篇文章。好像是同一个话题。我不知道这是Teradata语法。我不相信Teradata已经实现了对LAG的支持。我相信它依赖于OVER()窗口函数中的前行和后行子句来完成超前和滞后。谢谢Gordon和Rob。我相信罗布是对的。您知道如何使用“行前置”语法实现这一点吗?请参阅下面的@dnoeth response。TD14.10实现了
第一个值
和最后一个值,这是关于前置和滞后的更通用版本`