SELECT DC_GRP.dc_grp, DC_GRPX.reqt_id,
AVG(RESULTS.[var]) AS Average, STDEV(RESULTS.[var]) AS StdDev
FROM RESULTS INNER JOIN...
目前,我正在从 RESULTS 中提取所有 var 字段,但我只需要获取最近的 100 个。我怎么能只调用该 AVG( ( 调用中最近的 100 个?
假设您有一列来定义最新的列,您可以使用子查询来执行此操作:
SELECT DC_GRP.dc_grp, DC_GRPX.reqt_id,
AVG(r.[var]) AS Average, STDEV(r.[var]) AS StdDev
FROM (select top 100 * from RESULTS order by CreatedAt desc) r INNER JOIN...
此示例假定列的名称为 CreatedAt
。