在 MySQL 中创建一个时间（半小时）表

Question

For reporting purposes I need a Time table that acts as a lookup table that lists every half hour in a day. It will function the same way as a date table except it's time.

I found a great example of a 24 hour table:

    CREATE TABLE hourly_data
(
    id INT PRIMARY KEY AUTO_INCREMENT,
    date DATE NOT NULL,
    hour INT NOT NULL,
    f1 INT NOT NULL,
    f2 INT NOT NULL,
    f3 INT NOT NULL,
    f4 INT NOT NULL,
    f5 INT NOT NULL,
    f6 INT NOT NULL,
    inserted timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)

But I would rather it be every half hour. Any ideas on how to do this? This would help with shifts and create specialized reports. Thanks in advance!

Answer 1

in mariadb you can direct use the sequence Engine like this:

SELECT
  date('2010/01/01') + interval (seq * 30) Minute as mydate
FROM seq_0_to_10;

Sample

MariaDB [mysql]> select date('2010/01/01') + interval (seq * 30) Minute as mydate from seq_0_to_10;
+---------------------+
| mydate              |
+---------------------+
| 2010-01-01 00:00:00 |
| 2010-01-01 00:30:00 |
| 2010-01-01 01:00:00 |
| 2010-01-01 01:30:00 |
| 2010-01-01 02:00:00 |
| 2010-01-01 02:30:00 |
| 2010-01-01 03:00:00 |
| 2010-01-01 03:30:00 |
| 2010-01-01 04:00:00 |
| 2010-01-01 04:30:00 |
| 2010-01-01 05:00:00 |
+---------------------+
11 rows in set (0.00 sec)

MariaDB [mysql]>

old way without SEQUENCE Engine

SELECT
  DATE('2010/01/01') + INTERVAL (NR * 30) MINUTE AS mydate
FROM (
  SELECT d2.a*10+d1.a  AS nr FROM (
   SELECT 0  a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 
   UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8  UNION ALL SELECT 9) AS d1
   CROSS JOIN (
   SELECT 0 a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4  ) AS d2
WHERE d2.a*10+d1.a BETWEEN 0 AND 47
) AS parameter
ORDER BY nr;

sample

MariaDB [(none)]> SELECT
    ->   DATE('2010/01/01') + INTERVAL (NR * 30) MINUTE AS mydate
    -> FROM (
    ->   SELECT d2.a*10+d1.a  AS nr FROM (
    ->    SELECT 0  a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4
    ->    UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8  UNION ALL SELECT 9) AS d1
    ->    CROSS JOIN (
    ->    SELECT 0 a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4  ) AS d2
    -> WHERE d2.a*10+d1.a BETWEEN 0 AND 47
    -> ) AS parameter
    -> ORDER BY nr;
+---------------------+
| mydate              |
+---------------------+
| 2010-01-01 00:00:00 |
| 2010-01-01 00:30:00 |
| 2010-01-01 01:00:00 |
| 2010-01-01 01:30:00 |
| 2010-01-01 02:00:00 |
| 2010-01-01 02:30:00 |
| 2010-01-01 03:00:00 |
| 2010-01-01 03:30:00 |
| 2010-01-01 04:00:00 |
| 2010-01-01 04:30:00 |
| 2010-01-01 05:00:00 |
| 2010-01-01 05:30:00 |
| 2010-01-01 06:00:00 |
| 2010-01-01 06:30:00 |
| 2010-01-01 07:00:00 |
| 2010-01-01 07:30:00 |
| 2010-01-01 08:00:00 |
| 2010-01-01 08:30:00 |
| 2010-01-01 09:00:00 |
| 2010-01-01 09:30:00 |
| 2010-01-01 10:00:00 |
| 2010-01-01 10:30:00 |
| 2010-01-01 11:00:00 |
| 2010-01-01 11:30:00 |
| 2010-01-01 12:00:00 |
| 2010-01-01 12:30:00 |
| 2010-01-01 13:00:00 |
| 2010-01-01 13:30:00 |
| 2010-01-01 14:00:00 |
| 2010-01-01 14:30:00 |
| 2010-01-01 15:00:00 |
| 2010-01-01 15:30:00 |
| 2010-01-01 16:00:00 |
| 2010-01-01 16:30:00 |
| 2010-01-01 17:00:00 |
| 2010-01-01 17:30:00 |
| 2010-01-01 18:00:00 |
| 2010-01-01 18:30:00 |
| 2010-01-01 19:00:00 |
| 2010-01-01 19:30:00 |
| 2010-01-01 20:00:00 |
| 2010-01-01 20:30:00 |
| 2010-01-01 21:00:00 |
| 2010-01-01 21:30:00 |
| 2010-01-01 22:00:00 |
| 2010-01-01 22:30:00 |
| 2010-01-01 23:00:00 |
| 2010-01-01 23:30:00 |
+---------------------+
48 rows in set (0.00 sec)

Answer 2

I could not get the initial answer to work in MYSQL but by breaking down the second old school way. I replaced all the unions using the following query:

WITH RECURSIVE seq AS (SELECT 0 AS value UNION ALL SELECT value + 1 FROM seq WHERE value < 47) SELECT * FROM seq;

I then adjusted the initial query to use the above query to get the result:

WITH RECURSIVE seq AS (SELECT 0 AS value UNION ALL SELECT value + 1 FROM seq WHERE value < 47) SELECT DATE('2010/01/01') + INTERVAL (value * 30) MINUTE AS mydate FROM seq AS parameter ORDER BY value;

For just a list of times:

WITH RECURSIVE seq AS (SELECT 0 AS value UNION ALL SELECT value + 1 FROM seq WHERE value < 47 ) select time(DATE('2010/01/01') + INTERVAL (value * 30) minute) AS Time FROM seq AS parameter ORDER BY value;