我在我的网站上使用 CRON UI 为某些用户任务创建重复发生的计划。 UI 生成 CRON 格式，该格式存储在数据库中，我正在寻找一种方法来获取下一个运行时间，以了解任务是否到期并相应地执行该任务。有没有办法可以转换 CRON 格式以获得 SQL 中的下一次运行时间？
0 9 1-7 * 1 * First Monday of each month, at 9 a.m.
0 0 1 * * * At midnight, on the first day of each month
* 0-11 * * * Each minute before midday
桌子
JobID, CRONSchedule
1 0 9 1-7 * 1 *
2 0 0 1 * * *
3 * 0-11 * * *
SQL
Select JobID, CRONSchedule, NextRunTime from TABLE
我使用此查询来确定特定的 cron 是否已准备好运行（返回 t/f）。基于此查询，您可以获得下一次运行日期和时间，更新表中存在的列，并可以执行各种此类作业。但这段代码有局限性，我们只能输入 5 位结构的 cron 数据。
* * * * * command
| | | | |
| | | | +----- Day of the week (0 - 6) (Sunday is both 0 and 7)
| | | +------- Month (1 - 12)
| | +--------- Day of the month (1 - 31)
| +----------- Hour (0 - 23)
+------------- Minute (0 - 59)
这将是我的表格结构
Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
--------+-----------------------------+-----------+----------+--------------------------------------+----------+-------------+--------------+-------------
timeid | integer | | not null | nextval('time_timeid_seq'::regclass) | plain | | |
time | timestamp without time zone | | | | plain | | |
cron | character varying | | | | extended | | |
WITH TABLE_1 AS (
SELECT
TIMEID,
TIME,
CRON,
EXTRACT(MINUTE FROM now()) AS TIME_MINUTE,
EXTRACT(HOUR FROM now()) AS TIME_HOUR,
EXTRACT(DAY FROM now()) AS TIME_DAY_OF_MONTH,
EXTRACT(MONTH FROM now()) AS TIME_MONTH,
EXTRACT(DOW FROM now()) AS TIME_DAY_OF_WEEK,
(STRING_TO_ARRAY(CRON,' '))[1] AS CRON_MINUTE,
(STRING_TO_ARRAY(CRON,' '))[2] AS CRON_HOUR,
(STRING_TO_ARRAY(CRON,' '))[3] AS CRON_DAY_OF_MONTH,
(STRING_TO_ARRAY(CRON,' '))[4] AS CRON_MONTH,
(STRING_TO_ARRAY(CRON,' '))[5] AS CRON_DAY_OF_WEEK,
CASE
WHEN SPLIT_PART(CRON, ' ', 1) LIKE '*/%' THEN SUBSTRING(SPLIT_PART(CRON, ' ', 1) FROM 3)::INT
WHEN SPLIT_PART(CRON, ' ', 1) ~ '^[0-9]+$' THEN CAST(SPLIT_PART(CRON, ' ', 1) AS INT)
WHEN SPLIT_PART(CRON, ' ', 1) = '*' THEN 0
WHEN SPLIT_PART(CRON, ' ', 1) ~ '^[0-9]+-[0-9]+$' THEN (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 1), '-'))[1]::INT * 100 + (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 1), '-'))[2]::INT
ELSE NULL
END AS EXTRACTED_CRON_MINUTE_VALUE,
CASE
WHEN SPLIT_PART(CRON, ' ', 2) LIKE '*/%' THEN SUBSTRING(SPLIT_PART(CRON, ' ', 2) FROM 3)::INT
WHEN SPLIT_PART(CRON, ' ', 2) ~ '^[0-9]+$' THEN CAST(SPLIT_PART(CRON, ' ', 2) AS INT)
WHEN SPLIT_PART(CRON, ' ', 2) = '*' THEN 0
WHEN SPLIT_PART(CRON, ' ', 2) ~ '^[0-9]+-[0-9]+$' THEN (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 2), '-'))[1]::INT * 100 + (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 2), '-'))[2]::INT
ELSE NULL
END AS EXTRACTED_CRON_HOUR_VALUE,
CASE
WHEN SPLIT_PART(CRON, ' ', 3) LIKE '*/%' THEN SUBSTRING(SPLIT_PART(CRON, ' ', 3) FROM 3)::INT
WHEN SPLIT_PART(CRON, ' ', 3) ~ '^[0-9]+$' THEN CAST(SPLIT_PART(CRON, ' ', 3) AS INT)
WHEN SPLIT_PART(CRON, ' ', 3) = '*' THEN 0
WHEN SPLIT_PART(CRON, ' ', 3) ~ '^[0-9]+-[0-9]+$' THEN (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 3), '-'))[1]::INT * 100 + (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 3), '-'))[2]::INT
ELSE NULL
END AS EXTRACTED_CRON_DAY_OF_MONTH_VALUE,
CASE
WHEN SPLIT_PART(CRON, ' ', 4) LIKE '*/%' THEN SUBSTRING(SPLIT_PART(CRON, ' ', 4) FROM 3)::INT
WHEN SPLIT_PART(CRON, ' ', 4) ~ '^[0-9]+$' THEN CAST(SPLIT_PART(CRON, ' ', 4) AS INT)
WHEN SPLIT_PART(CRON, ' ', 4) = '*' THEN 0
WHEN SPLIT_PART(CRON, ' ', 4) ~ '^[0-9]+-[0-9]+$' THEN (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 4), '-'))[1]::INT * 100 + (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 4), '-'))[2]::INT
ELSE NULL
END AS EXTRACTED_CRON_MONTH_VALUE,
CASE
WHEN SPLIT_PART(CRON, ' ', 5) LIKE '*/%' THEN SUBSTRING(SPLIT_PART(CRON, ' ', 5) FROM 3)::INT
WHEN SPLIT_PART(CRON, ' ', 5) ~ '^[0-9]+$' THEN CAST(SPLIT_PART(CRON, ' ', 5) AS INT)
WHEN SPLIT_PART(CRON, ' ', 5) = '*' THEN 0
WHEN SPLIT_PART(CRON, ' ', 5) ~ '^[0-9]+-[0-9]+$' THEN (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 5), '-'))[1]::INT * 100 + (STRING_TO_ARRAY(SPLIT_PART(CRON, ' ', 5), '-'))[2]::INT
ELSE NULL
END AS EXTRACTED_CRON_DAY_OF_WEEK_VALUE
FROM
TIME
), TABLE_2 AS (
SELECT
TIMEID,
TIME,
CRON,
TIME_MINUTE,
TIME_HOUR,
TIME_DAY_OF_MONTH,
TIME_MONTH,
TIME_DAY_OF_WEEK,
EXTRACTED_CRON_MINUTE_VALUE,
EXTRACTED_CRON_HOUR_VALUE,
EXTRACTED_CRON_DAY_OF_MONTH_VALUE,
EXTRACTED_CRON_MONTH_VALUE,
EXTRACTED_CRON_DAY_OF_WEEK_VALUE,
CASE
WHEN CRON_MINUTE LIKE '*/%' AND TIME_MINUTE % EXTRACTED_CRON_MINUTE_VALUE = 0 THEN TRUE
WHEN CRON_MINUTE ~ '^[0-9]+$' AND TIME_MINUTE - EXTRACTED_CRON_MINUTE_VALUE = 0 THEN TRUE
WHEN CRON_MINUTE = '*' THEN TRUE
WHEN CRON_MINUTE ~ '^[0-9]+-[0-9]+$' AND
TIME_MINUTE = EXTRACTED_CRON_MINUTE_VALUE / 100 OR TIME_MINUTE = EXTRACTED_CRON_MINUTE_VALUE % 10 OR (TIME_MINUTE BETWEEN EXTRACTED_CRON_MINUTE_VALUE / 100
AND EXTRACTED_CRON_MINUTE_VALUE % 10) THEN TRUE
ELSE FALSE
END AS RESULT_MINUTE,
CASE
WHEN CRON_HOUR LIKE '*/%' AND TIME_HOUR % EXTRACTED_CRON_HOUR_VALUE = 0 THEN TRUE
WHEN CRON_HOUR ~ '^[0-9]+$' AND TIME_HOUR - EXTRACTED_CRON_HOUR_VALUE = 0 THEN TRUE
WHEN CRON_HOUR = '*' THEN TRUE
WHEN CRON_HOUR ~ '^[0-9]+-[0-9]+$' AND
TIME_HOUR = EXTRACTED_CRON_HOUR_VALUE / 100 OR TIME_HOUR = EXTRACTED_CRON_HOUR_VALUE % 10 OR (TIME_HOUR BETWEEN EXTRACTED_CRON_HOUR_VALUE / 100
AND EXTRACTED_CRON_HOUR_VALUE % 10) THEN TRUE
ELSE FALSE
END AS RESULT_HOUR,
CASE
WHEN CRON_DAY_OF_MONTH LIKE '*/%' AND TIME_DAY_OF_MONTH % EXTRACTED_CRON_DAY_OF_MONTH_VALUE = 0 THEN TRUE
WHEN CRON_DAY_OF_MONTH ~ '^[0-9]+$' AND TIME_DAY_OF_MONTH - EXTRACTED_CRON_DAY_OF_MONTH_VALUE = 0 THEN TRUE
WHEN CRON_DAY_OF_MONTH = '*' THEN TRUE
WHEN CRON_DAY_OF_MONTH ~ '^[0-9]+-[0-9]+$' AND
TIME_DAY_OF_MONTH = EXTRACTED_CRON_DAY_OF_MONTH_VALUE / 100 OR TIME_DAY_OF_MONTH = EXTRACTED_CRON_DAY_OF_MONTH_VALUE % 10 OR (TIME_DAY_OF_MONTH BETWEEN EXTRACTED_CRON_DAY_OF_MONTH_VALUE / 100
AND EXTRACTED_CRON_DAY_OF_MONTH_VALUE % 10) THEN TRUE
ELSE FALSE
END AS RESULT_DAY_OF_MONTH,
CASE
WHEN CRON_MONTH LIKE '*/%' AND TIME_MONTH % EXTRACTED_CRON_MONTH_VALUE = 0 THEN TRUE
WHEN CRON_MONTH ~ '^[0-9]+$' AND TIME_MONTH - EXTRACTED_CRON_MONTH_VALUE = 0 THEN TRUE
WHEN CRON_MONTH = '*' THEN TRUE
WHEN CRON_MONTH ~ '^[0-9]+-[0-9]+$' AND
TIME_MONTH = EXTRACTED_CRON_MONTH_VALUE / 100 OR TIME_MONTH = EXTRACTED_CRON_MONTH_VALUE % 10 OR (TIME_MONTH BETWEEN EXTRACTED_CRON_MONTH_VALUE / 100
AND EXTRACTED_CRON_MONTH_VALUE % 10) THEN TRUE
ELSE FALSE
END AS RESULT_MONTH,
CASE
WHEN CRON_DAY_OF_WEEK LIKE '*/%' AND TIME_DAY_OF_WEEK % EXTRACTED_CRON_DAY_OF_WEEK_VALUE = 0 THEN TRUE
WHEN CRON_DAY_OF_WEEK ~ '^[0-9]+$' AND TIME_DAY_OF_WEEK - EXTRACTED_CRON_DAY_OF_WEEK_VALUE = 0 THEN TRUE
WHEN CRON_DAY_OF_WEEK = '*' THEN TRUE
WHEN CRON_DAY_OF_WEEK ~ '^[0-9]+-[0-9]+$' AND
TIME_DAY_OF_WEEK = EXTRACTED_CRON_DAY_OF_WEEK_VALUE / 100 OR TIME_DAY_OF_WEEK = EXTRACTED_CRON_DAY_OF_WEEK_VALUE % 10 OR (TIME_DAY_OF_WEEK BETWEEN EXTRACTED_CRON_DAY_OF_WEEK_VALUE / 100
AND EXTRACTED_CRON_DAY_OF_WEEK_VALUE % 10) THEN TRUE
ELSE FALSE
END AS RESULT_DAY_OF_WEEK
FROM TABLE_1
)
SELECT
TIMEID,
CRON,
RESULT_MINUTE,
RESULT_HOUR,
RESULT_DAY_OF_MONTH,
RESULT_MONTH,
RESULT_DAY_OF_WEEK,
CASE
WHEN (RESULT_MINUTE) = TRUE AND (RESULT_HOUR) AND (RESULT_DAY_OF_MONTH) = TRUE AND (RESULT_MONTH) = TRUE AND (RESULT_DAY_OF_WEEK) = TRUE THEN TRUE
ELSE FALSE
END AS RESULT
FROM TABLE_2;
我希望这段代码有帮助！！