mysql - 在MySQL中创建一个时间(半小时)表

Question

出于报告目的，我需要一个时间表作为查找表，列出一天中每半小时的信息。除了时间之外，它的功能与日期表相同。

我找到了一个很好的 24 小时表示例:

    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
)

但我宁愿每半小时一次。关于如何做到这一点有什么想法吗？这将有助于轮类并创建专门的报告。提前致谢!

Answer 1

在mariadb中你可以直接使用序列引擎，如下所示:

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

示例

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]>

没有 SEQUENCE 引擎的旧方法

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;

示例

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)