如何使用分析为我提供样本量变化的滚动平均值？
create table MyVals (Item_no char(10), epoch number, Yield number, Skip_Period char(1), Reset_Period char(1));
insert into MyVals values ('A00001',1705, 12, 'N','N'); /* 17.18181818 average of epochs 1705..1610 & 1607..1606 */
insert into MyVals values ('A00001',1704, 13, 'N','N'); /* 19.45454545 average of epochs 1704..1610 & 1607..1605 */
insert into MyVals values ('A00001',1703, 9, 'N','N'); /* 20.36363636 average of epochs 1703..1610 & 1607..1604 */
insert into MyVals values ('A00001',1702, 11, 'N','N'); /* 21.5 average of epochs 1702..1610 & 1607..1604 */
insert into MyVals values ('A00001',1701, 4, 'N','N'); /* 22.66666667 average of epochs 1701..1610 & 1607..1604 */
insert into MyVals values ('A00001',1613, 16, 'N','N'); /* 25 average of epochs 1613..1610 & 1607..1604 */
insert into MyVals values ('A00001',1612, 33, 'N','N'); /* 26.28571429 average of epochs 1612..1610 & 1607..1604 */
insert into MyVals values ('A00001',1611, 2, 'N','N'); /* 25.16666667 average of epochs 1611..1610 & 1607..1604 */
insert into MyVals values ('A00001',1610, 1, 'N','N'); /* 29.8 average of epochs 1610 & 1607..1604 */
insert into MyVals values ('A00001',1609, 66, 'Y','N'); /* 37 average of epochs 1607..1604 */
insert into MyVals values ('A00001',1608, 23, 'Y','N'); /* 37 average of epochs 1607..1604 */
insert into MyVals values ('A00001',1607, 22, 'N','N'); /* 37 average of epochs 1607..1604 */
insert into MyVals values ('A00001',1606, 66, 'N','N'); /* 42 average of epochs 1606..1604 */
insert into MyVals values ('A00001',1605, 37, 'N','N'); /* 30 average of epochs 1605..1604 */
insert into MyVals values ('A00001',1604, 23, 'N','Y'); /* 23 average of epochs 1604 */
insert into MyVals values ('A00001',1603, 77, 'N','N'); /* 44.83333333 average of epochs 1603..1511 */
insert into MyVals values ('A00001',1602, 15, 'N','N'); /* 38.4 average of epochs 1602..1511 */
insert into MyVals values ('A00001',1601, 82, 'N','N'); /* 44.25 average of epochs 1601..1511 */
insert into MyVals values ('A00001',1513, 4, 'N','N'); /* 31.66666667 average of epochs 1513..1511 */
insert into MyVals values ('A00001',1512, 7, 'N','N'); /* 45.5 average of epochs 1512..1511 */
insert into MyVals values ('A00001',1511, 84, 'N','N'); /* 84 average of epochs 1511 */
如何获得前一个最大13条记录的平均收益率，其中Skip_Period =＆＃39; N＆＃39;而Reset_Period =＆＃39; N＆＃39;
因此，平均值的窗口会根据skip_Period和Reset_Period的值发生变化，具体取决于以下规则：
如果某行有Reset_Period =＆＃39; Y＆＃39;，则不要再返回该记录。 如果某行有Skip_period =＆＃39; Y＆＃39;，则从平均样本中排除该句号
我无法想象如何在表达式之间创建一个范围，这样我就可以使用分析来获得滚动平均值。
欢迎任何建议：）
答案 0 :(得分：1)
我认为这就是你所追求的：
WITH res AS (SELECT item_no,
epoch_number,
yield,
skip_period,
reset_period,
SUM(CASE WHEN reset_period = 'Y' THEN 1 ELSE 0 END) OVER (PARTITION BY item_no ORDER BY epoch_number) grp
FROM myvals)
SELECT item_no,
epoch_number,
yield,
skip_period,
reset_period,
grp,
AVG(CASE WHEN skip_period = 'N' THEN yield END) OVER (PARTITION BY item_no, grp
ORDER BY epoch_number
rows 12 preceding) rolling_avg_yield
FROM res
ORDER BY epoch_number DESC;
ITEM_NO EPOCH_NUMBER YIELD SKIP_PERIOD RESET_PERIOD GRP ROLLING_AVG_YIELD
------- ------------ ---------- ----------- ------------ ---------- -----------------
A00001 1705 12 N N 1 17.1818181818182
A00001 1704 13 N N 1 19.4545454545455
A00001 1703 9 N N 1 20.3636363636364
A00001 1702 11 N N 1 21.5
A00001 1701 4 N N 1 22.6666666666667
A00001 1613 16 N N 1 25
A00001 1612 33 N N 1 26.2857142857143
A00001 1611 2 N N 1 25.1666666666667
A00001 1610 1 N N 1 29.8
A00001 1609 66 Y N 1 37
A00001 1608 23 Y N 1 37
A00001 1607 22 N N 1 37
A00001 1606 66 N N 1 42
A00001 1605 37 N N 1 30
A00001 1604 23 N Y 1 23
A00001 1603 77 N N 0 44.8333333333333
A00001 1602 15 N N 0 38.4
A00001 1601 82 N N 0 44.25
A00001 1513 4 N N 0 31.6666666666667
A00001 1512 7 N N 0 45.5
A00001 1511 84 N N 0 84
首先，您需要计算出您平均的群体。我们可以通过根据报告组是否更改生成值1或0，然后对这些值进行运行求和来实现此目的。
一旦我们拥有了这个，只需要在分区中包含该列，然后如果跳过周期为N，则在当前行和前12行之间执行条件平均。