mysql 實現類似 postgresql 數據庫的 generate_series 函數

os: centos 7.4.1708
db: mysql 8.0.20

版本

# cat /etc/centos-release
CentOS Linux release 7.4.1708 (Core) 
# 
# 
# yum list installed |grep -i mysql80
mysql-community-client.x86_64              8.0.20-1.el7                @mysql80-community
mysql-community-common.x86_64              8.0.20-1.el7                @mysql80-community
mysql-community-devel.x86_64               8.0.20-1.el7                @mysql80-community
mysql-community-libs.x86_64                8.0.20-1.el7                @mysql80-community
mysql-community-libs-compat.x86_64         8.0.20-1.el7                @mysql80-community
mysql-community-server.x86_64              8.0.20-1.el7                @mysql80-community
mysql-community-test.x86_64                8.0.20-1.el7                @mysql80-community
mysql80-community-release.noarch           el7-3                       installed

# mysql -e "select version();"
+-----------+
| version() |
+-----------+
| 8.0.20    |
+-----------+

generate_seed

mysql> use test

mysql> DELIMITER $$
 
DROP PROCEDURE IF EXISTS `generate_seed`$$
 
CREATE PROCEDURE `generate_seed`(
    IN f_begin_num INT UNSIGNED, 
	IN f_end_num   INT UNSIGNED 
)
BEGIN 
    DROP TABLE IF EXISTS generate_seed_tmp;
    CREATE TEMPORARY TABLE generate_seed_tmp (id INT);
	BEGIN
	  DECLARE i INT;
	  SET i = f_begin_num;
	  WHILE i <= f_end_num DO
	    INSERT INTO generate_seed_tmp VALUES (i);
	    SET i = i + 1;
	  END WHILE;
	END;
END$$
 
DELIMITER ;

使用

mysql> call generate_seed(1,100);

mysql> select @a := @a + 1 as seq, date_sub(current_date(), interval @a day) from generate_seed_tmp,(select @a:=0) as seq;

+------+-------------------------------------------+
| seq  | date_sub(current_date(), interval @a day) |
+------+-------------------------------------------+
|    1 | 2020-06-30                                |
|    2 | 2020-06-29                                |
|    3 | 2020-06-28                                |
|    4 | 2020-06-27                                |
|    5 | 2020-06-26                                |
···
···
···
|   96 | 2020-03-27                                |
|   97 | 2020-03-26                                |
|   98 | 2020-03-25                                |
|   99 | 2020-03-24                                |
|  100 | 2020-03-23                                |
+------+-------------------------------------------+
100 rows in set, 2 warnings (0.00 sec)