我试图在一段时间内保持平均水平(例如:过去6个月,上个月,上周......)。
为此,我创建了4个查询。我可以清楚地做点什么吗?
/** ON SELECTED DATE*/
SELECT AVG(RUN_TIME)
FROM (SELECT (DATEDIFF(minute,MIN(CAST(START_DATE AS DATETIME)), MAX(CAST(END_DATE AS DATETIME)))) as RUN_TIME FROM TableTest where DATE_EXPECTED = DATE_SELECTED ) f
/**ON 6 last month*/
SELECT AVG(RUN_TIME)
FROM (SELECT (DATEDIFF(minute,MIN(CAST(START_DATE AS DATETIME)), MAX(CAST(END_DATE AS DATETIME)))) as RUN_TIME FROM TableTest
where Month(CAST(DATE_SELECTED AS DATETIME)) BETWEEN Month(CAST(DATE_SELECTED AS DATETIME) ) AND Month(CAST(DATE_SELECTED AS DATETIME) )+6 ) f
/** on 30 last days */
SELECT AVG(RUN_TIME)
FROM (SELECT (DATEDIFF(minute,MIN(CAST(START_DATE AS DATETIME)), MAX(CAST(END_DATE AS DATETIME)))) as RUN_TIME FROM TableTest where DATE_EXPECTED between DATE_SELECTED and DATE_SELECTED+30) f
/* on 5 last days */
SELECT AVG(RUN_TIME)
FROM (SELECT (DATEDIFF(minute,MIN(CAST(START_DATE AS DATETIME)), MAX(CAST(END_DATE AS DATETIME)))) as RUN_TIME FROM TableTest where DATE_EXPECTED between DATE_SELECTED and DATE_SELECTED+5 ) f
它正在运作,但我想知道我是否能以最好的方式做这件事。
谢谢,
答案 0 :(得分:2)
您可以使用条件聚合:
SELECT AVG(CASE WHEN DATE_EXPECTED = DATE_SELECTED THEN RUN_TIME END) as avg_1,
AVG(CASE WHEN Month(CAST(DATE_SELECTED AS DATETIME)) BETWEEN Month(CAST(DATE_SELECTED AS DATETIME) ) AND Month(CAST(DATE_SELECTED AS DATETIME) )+6 THEN RUN_TIME END) as avg_2,
AVG(CASE WHEN DATE_EXPECTED between DATE_SELECTED and DATE_SELECTED+30 THEN RUN_TIME END) as avg_3,
AVG(CASE WHEN DATE_EXPECTED between DATE_SELECTED and DATE_SELECTED+5 THEN RUN_TIME END) as avg_4
FROM (SELECT (DATEDIFF(minute,MIN(CAST(START_DATE AS DATETIME)), MAX(CAST(END_DATE AS DATETIME)))) as RUN_TIME
FROM TableTest
) f;