请教大神,对MYSQL数据表TMPtable,想针对name 列,计算每5天的平均值,代码如下,但计算后一直为NULL,代码哪里错了?
SELECT b.*,
(
SELECT avg(t1.`close`) from (
SELECT t.*,(@rownum := @rownum + 1) AS rownum FROM (SELECT @rownum := 0) r,`TMPtable` t ORDER BY `name`,`index` asc) t1
WHERE t1.rownum <= b.rownum + 5 and t1.rownum > b.rownum
)avg5
from
( select b.*,(@rownum := @rownum + 1) AS rownum FROM (SELECT @rownum := 0) r,`TMPtable` b ORDER BY `name`,`index` asc) b
计算前:
计算后: