下面是這篇文章中我的博客略微修改的方案:
DECLARE @t TABLE
(
q_start DATETIME NOT NULL,
q_end DATETIME NOT NULL
)
DECLARE @qs DATETIME
DECLARE @qe DATETIME
DECLARE @ms DATETIME
DECLARE @me DATETIME
DECLARE cr_span CURSOR FAST_FORWARD
FOR
SELECT s_timestamp AS q_start,
DATEADD(minute, 1, s_timestamp) AS q_end
FROM [20090611_timespans].t_span
ORDER BY
q_start
OPEN cr_span
FETCH NEXT
FROM cr_span
INTO @qs, @qe
SET @ms = @qs
SET @me = @qe
WHILE @@FETCH_STATUS = 0
BEGIN
FETCH NEXT
FROM cr_span
INTO @qs, @qe
IF @qs > @me
BEGIN
INSERT
INTO @t
VALUES (@ms, @me)
SET @ms = @qs
END
SET @me = CASE WHEN @qe > @me THEN @qe ELSE @me END
END
IF @ms IS NOT NULL
BEGIN
INSERT
INTO @t
VALUES (@ms, @me)
END
CLOSE cr_span
這將返回連續範圍時更新確實發生了(與一分鐘決議)。
如果您在timestamp
場有一個指標,你可能會發出以下查詢:
SELECT *
FROM records ro
WHERE NOT EXISTS
(
SELECT NULL
FROM records ri
WHERE ri.timestamp >= DATEADD(minute, -1, ro.timestamp)
AND ri.timestamp < ro.timestamp
)