sql urutan hari tanpa tabel

1. MySQL/MariaDB. gak paham sama sekali, gimana cara kerja skrip ini. https://stackoverflow.com/a/5081980

set @awal := '2023-03-01', @akhir := '2023-03-31';
SELECT @awal + INTERVAL a + b DAY `date`
FROM
 (SELECT 0 a UNION SELECT 1 a UNION SELECT 2 UNION SELECT 3
    UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7
    UNION SELECT 8 UNION SELECT 9 ) d,
 (SELECT 0 b UNION SELECT 10 UNION SELECT 20 
    UNION SELECT 30 UNION SELECT 40) m
WHERE @awal + INTERVAL a + b DAY  <=  @akhir
ORDER BY a + b
limit 999

2. MariaDB. keren banget ini, langsung paham (output nya sama dengan #1). https://stackoverflow.com/a/54833745 https://mariadb.com/kb/en/sequence-storage-engine/

set @awal := '2023-03-01', @akhir := '2023-03-31';
SELECT @awal + interval seq day as `date` FROM seq_0_to_365
WHERE @awal + interval seq day  <= @akhir
limit 999