如何从 SQL 的一组时间范围中删除特定的时间范围？

Question

With this example set of timestamp ranges:

WITH sessions AS (
  (
  SELECT 
    TIMESTAMP('2022-09-24 13:49:32+0100') AS start,
    TIMESTAMP('2022-09-26 02:06:17+0100') AS end
  
  UNION ALL
  
  SELECT
    TIMESTAMP('2022-09-26 08:42:19+0100'), 
    TIMESTAMP('2022-09-26 09:41:40+0100'),  

  UNION ALL
 
  SELECT
    TIMESTAMP('2022-09-26 09:53:06+0100'),
    TIMESTAMP('2022-09-26 11:20:34+0100'))
)

SELECT * FROM sessions WHERE.... 

How would I go about removing all time between Fridays 17:00, America/New_York and Monday 09:00 Asia/Shanghai?

I really can't seem to figure this out.

"Best" thing I can think of is generating a table with all Friday/Monday ranges, and joining against that table, using the standard Gaps and Islands solution, is that really the best way?

Thanks!

Edit:

The context is wait and resolution times for a ticketing system, where only time within the open operating hours should count. The service is staffed by various international teams, so the services operating hours become more complicated.

I would expect the results to look like this:

Start                     End                       Status
2022-09-24 13:49:32+0100  2022-09-26 02:00:00+0100  Closed
2022-09-26 02:00:00+0100  2022-09-26 02:06:17+0100  Open
2022-09-26 08:42:19+0100  2022-09-26 09:41:40+0100  Open
2022-09-26 09:53:06+0100  2022-09-26 11:20:34+0100  Open

Because the part of the 26th is within the working hours of Shanghai.

Answer 1

Assuming Monday 09:00 Asia/Shanghai corresponds to Sunday 21:00 America/New_York I came up with the following (I only filtered by the column start , if necessary you can apply the same to end ):

WITH sessions AS (
  (
  SELECT TIMESTAMP('2022-09-24T13:49:32+0100') AS `start`, TIMESTAMP('2022-09-26T02:06:17+0100') AS `end` UNION ALL
  SELECT TIMESTAMP('2022-09-26T08:42:19+0100'), TIMESTAMP('2022-09-26T09:41:40+0100'),  UNION ALL
  SELECT TIMESTAMP('2022-09-26T09:53:06+0100'), TIMESTAMP('2022-09-26T11:20:34+0100')) 
)

SELECT *
FROM sessions 
WHERE 
  NOT (
    (EXTRACT(DAYOFWEEK FROM start AT TIME ZONE 'America/New_York') = 6 AND EXTRACT(TIME FROM start AT TIME ZONE 'America/New_York') > TIME(17, 0, 0))
    OR 
    (EXTRACT(DAYOFWEEK FROM start AT TIME ZONE 'America/New_York') = 7)
    OR 
    (EXTRACT(DAYOFWEEK FROM start AT TIME ZONE 'America/New_York') = 1 AND EXTRACT(TIME FROM start AT TIME ZONE 'America/New_York') < TIME(21, 0, 0))
  )

Short explanation:
DAYOFWEEK gives you the weekday, Sundays being 1 ( see docs ). For Friday and Sunday I also compare the times with the thresholds and exclude them from the results, Saturday I exclude completely.

The following will exclude all periods that fall in the closed time. Periods that overlap with the closed time are truncated. Only periods in open time are returned. Added a few comments for explaining the query:

-- Assuming closed period in UTC is from Friday 22:00 to Monday 01:00
-- Assuming start and end do not span over the closed period

WITH sessions AS (
  (
  SELECT TIMESTAMP('2022-09-24T13:49:32+0100') AS `start`, TIMESTAMP('2022-09-26T02:06:17+0100') AS `end` UNION ALL
  SELECT TIMESTAMP('2022-09-26T08:42:19+0100'), TIMESTAMP('2022-09-26T09:41:40+0100'),  UNION ALL
  SELECT TIMESTAMP('2022-09-23T08:42:19+0100'), TIMESTAMP('2022-09-25T09:41:40+0100'),  UNION ALL
  SELECT TIMESTAMP('2022-09-26T09:53:06+0100'), TIMESTAMP('2022-09-26T11:20:34+0100')) 
)

SELECT 
CASE 
  WHEN start_offset IS NOT NULL THEN TIMESTAMP_ADD(TIMESTAMP(DATETIME(EXTRACT(YEAR FROM start), EXTRACT(MONTH FROM start), EXTRACT(DAY FROM start), 1, 0, 0)), INTERVAL start_offset DAY) 
  ELSE start
  END as new_start, -- using the determined offset, time is fixed
CASE 
  WHEN end_offset IS NOT NULL THEN TIMESTAMP_SUB(TIMESTAMP(DATETIME(EXTRACT(YEAR FROM `end`), EXTRACT(MONTH FROM `end`), EXTRACT(DAY FROM `end`), 22, 0, 0)), INTERVAL end_offset DAY)
  ELSE `end`
  END as new_end, -- using the determined offset, time is fixed
FROM
(
  SELECT 
  *,
  CASE 
    WHEN (EXTRACT(DAYOFWEEK FROM start) = 6 AND EXTRACT(TIME FROM start) > TIME(22, 0, 0)) THEN 3
    WHEN (EXTRACT(DAYOFWEEK FROM start) = 7) THEN 2
    WHEN (EXTRACT(DAYOFWEEK FROM start) = 1) THEN 1
    WHEN (EXTRACT(DAYOFWEEK FROM start) = 2 AND EXTRACT(TIME FROM start) < TIME(1, 0, 0)) THEN 0
    ELSE NULL
    END AS start_offset, -- determine how many days to offset the start (adding to start date)
  CASE 
    WHEN (EXTRACT(DAYOFWEEK FROM `end`) = 6 AND EXTRACT(TIME FROM `end`) > TIME(22, 0, 0)) THEN 0
    WHEN (EXTRACT(DAYOFWEEK FROM `end`) = 7) THEN 1
    WHEN (EXTRACT(DAYOFWEEK FROM `end`) = 1) THEN 2
    WHEN (EXTRACT(DAYOFWEEK FROM `end`) = 2 AND EXTRACT(TIME FROM `end`) < TIME(1, 0, 0)) THEN 3
    ELSE NULL
    END AS end_offset, -- determine how many days to offset the end (subtracting from end date)
  FROM sessions
)
WHERE NOT (start_offset IS NOT NULL AND end_offset IS NOT NULL)