mysql_generate_series is a MySQL version of PostgreSQL's generate_series functions.
This version is (heavily) adapted from the original and seeks to simplify the method call and make the MySQL version parameters follow the PostgreSQL version insofar as that is possible.
It offers a single method generate_series(start, stop, step) to deliver a series from start to stop incrementing by step.
Calling the method generates no output but instead creates a temporary table called series_tmp in the current database which can be used in joins and sub-queries in the current session.
All parameters are INTEGER or strings which are representative of INTEGER, DATE, DATETIME and INTERVAL depending on the type of series being generated
Install the methods from sql/generate_series.sql.
For integer ranges the three parameters are all INTEGER or string representations of numbers.
CALL generate_series(1, 20, 1);Will create and populate series_tmp with INTEGER values from 1 to 20, incrementing by 1.
mysql> CALL generate_series( 1 , 10 , 1);
Query OK, 0 rows affected (0.05 sec)
mysql> DESC series_tmp;
+--------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+------------+------+-----+---------+-------+
| series | bigint(20) | NO | PRI | NULL | |
+--------+------------+------+-----+---------+-------+
1 row in set (0.00 sec)
mysql> SELECT * FROM `series_tmp`;
+--------+
| series |
+--------+
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
| 6 |
| 7 |
| 8 |
| 9 |
| 10 |
+--------+
10 rows in set (0.00 sec)For date ranges the start and stop parameters are string representations of dates and step represents the INTERVAL.
CALL generate_series('2018-01-01','2018-12-31','INTERVAL 1 DAY');mysql> CALL generate_series('2018-01-01','2018-12-31','INTERVAL 1 MONTH');
Query OK, 0 rows affected (0.08 sec)
mysql> DESC series_tmp;
+--------+------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+------+------+-----+---------+-------+
| series | date | NO | PRI | NULL | |
+--------+------+------+-----+---------+-------+
1 row in set (0.00 sec)
mysql> SELECT * FROM `series_tmp`;
+------------+
| series |
+------------+
| 2018-01-01 |
| 2018-02-01 |
| 2018-03-01 |
| 2018-04-01 |
| 2018-05-01 |
| 2018-06-01 |
| 2018-07-01 |
| 2018-08-01 |
| 2018-09-01 |
| 2018-10-01 |
| 2018-11-01 |
| 2018-12-01 |
+------------+
12 rows in set (0.00 sec)For datetime ranges the start and stop parameters are datetimes and step represents the INTERVAL.
CALL generate_series('2018-01-01 00:00:00', '2018-01-01 23:59:59', 'INTERVAL 1 SECOND');mysql> CALL generate_series('2018-01-01 00:00:00', '2018-01-01 23:59:00', 'INTERVAL 1 MINUTE');
Query OK, 0 rows affected (0.07 sec)
mysql> DESC series_tmp;
+--------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+----------+------+-----+---------+-------+
| series | datetime | NO | PRI | NULL | |
+--------+----------+------+-----+---------+-------+
1 row in set (0.01 sec)
mysql> SELECT * FROM `series_tmp`;
+---------------------+
| series |
+---------------------+
| 2018-01-01 00:00:00 |
| 2018-01-01 00:01:00 |
| 2018-01-01 00:02:00 |
| 2018-01-01 00:03:00 |
| 2018-01-01 00:04:00 |
| 2018-01-01 00:05:00 |
| 2018-01-01 00:06:00 |
| 2018-01-01 00:07:00 |
| 2018-01-01 00:08:00 |
...
| 2018-01-01 23:56:00 |
| 2018-01-01 23:57:00 |
| 2018-01-01 23:58:00 |
| 2018-01-01 23:59:00 |
+---------------------+
1440 rows in set (0.00 sec)The following INTERVAL types are supported:
SECONDMINUTEHOURDAYWEEKMONTHYEAR
MySQL does not support functions returning tables so the procedure must be run before the data can be used from series_tmp.
The following example shows how to insert multiple rows in MySQL tables easily:
-- Create a test table
mysql> CREATE TABLE test (a int, b text);
Query OK, 0 rows affected (0.01 sec)
-- Generate a series from 1 to 10
mysql> CALL generate_series(1, 10, 1);
Query OK, 0 rows affected (0.00 sec)
-- Insert all the rows from the series into the test table
mysql> INSERT INTO test (a, b) SELECT series, 'This is a test' FROM `series_tmp`;
Query OK, 10 rows affected (0.00 sec)
Records: 10 Duplicates: 0 Warnings: 0
-- Display the test table content
mysql> SELECT * FROM test;
+------+----------------+
| a | b |
+------+----------------+
| 1 | This is a test |
| 2 | This is a test |
| 3 | This is a test |
| 4 | This is a test |
| 5 | This is a test |
| 6 | This is a test |
| 7 | This is a test |
| 8 | This is a test |
| 9 | This is a test |
| 10 | This is a test |
+------+----------------+
10 rows in set (0.00 sec)As for inserts, MySQL does not allow using a stored procedure directly in a SELECT query.
We can again use mysql_generate_series's temporary table series_tmp to use the series with a JOIN in a SELECT query
This example demonstrates how to display all hours from a date and their eventual associated row in another table:
-- Create test table
mysql> CREATE TABLE test2 (a datetime, b text);
Query OK, 0 rows affected (0.03 sec)
-- Insert 2 lines
mysql> INSERT INTO test2 (a, b) VALUES ('2015-09-03 02:00:00', 'Line 1'),
-> ('2015-09-03 14:00:00', 'Line 2');
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
-- Generate a series of each hour of the day
mysql> CALL generate_series('2015-09-03 00:00:00', '2015-09-03 23:00:00', 'INTERVAL 1 HOUR');
Query OK, 0 rows affected (0.00 sec)
-- Select "test2" content
mysql> SELECT * FROM test2;
+---------------------+--------+
| a | b |
+---------------------+--------+
| 2015-09-03 02:00:00 | Line 1 |
| 2015-09-03 14:00:00 | Line 2 |
+---------------------+--------+
2 rows in set (0.00 sec)
-- Select "test2" content with all hours of the day
mysql> SELECT series_tmp.series, test2.a, test2.b
-> FROM series_tmp
-> LEFT JOIN test2 ON series_tmp.series = test2.a
-> ORDER BY series_tmp.series;
+---------------------+---------------------+--------+
| series | a | b |
+---------------------+---------------------+--------+
| 2015-09-03 00:00:00 | NULL | NULL |
| 2015-09-03 01:00:00 | NULL | NULL |
| 2015-09-03 02:00:00 | 2015-09-03 02:00:00 | Line 1 |
| 2015-09-03 03:00:00 | NULL | NULL |
| 2015-09-03 04:00:00 | NULL | NULL |
| 2015-09-03 05:00:00 | NULL | NULL |
| 2015-09-03 06:00:00 | NULL | NULL |
| 2015-09-03 07:00:00 | NULL | NULL |
| 2015-09-03 08:00:00 | NULL | NULL |
| 2015-09-03 09:00:00 | NULL | NULL |
| 2015-09-03 10:00:00 | NULL | NULL |
| 2015-09-03 11:00:00 | NULL | NULL |
| 2015-09-03 12:00:00 | NULL | NULL |
| 2015-09-03 13:00:00 | NULL | NULL |
| 2015-09-03 14:00:00 | 2015-09-03 14:00:00 | Line 2 |
| 2015-09-03 15:00:00 | NULL | NULL |
| 2015-09-03 16:00:00 | NULL | NULL |
| 2015-09-03 17:00:00 | NULL | NULL |
| 2015-09-03 18:00:00 | NULL | NULL |
| 2015-09-03 19:00:00 | NULL | NULL |
| 2015-09-03 20:00:00 | NULL | NULL |
| 2015-09-03 21:00:00 | NULL | NULL |
| 2015-09-03 22:00:00 | NULL | NULL |
| 2015-09-03 23:00:00 | NULL | NULL |
+---------------------+---------------------+--------+
24 rows in set (0.00 sec)The temporary table used to store results series_tmp is dropped and recreated on each call to generate_series(). As a temporary table, series_tmp will only be available within the current session and to the current user. It will also automatically dropped when the connection is closed.
Gabriel Bordeaux
Paul Campbell
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