PROGRAMMING
Php
Order by rand
Order by rand is very slow. Order by index (random) is recommended.
SELECT * FROM article ORDER BY RAND() LIMIT 1;
ALTER TABLE article ADD random FLOAT NOT NULL;
ALTER TABLE ADD INDEX random (random);
UPDATE article SET random = RAND();
INSERT INTO article (..., random) VALUES (..., RAND());
SELECT * FROM article WHERE random >
(SELECT RAND() as rand) ORDER BY random LIMIT 1;
Daily Rand
Get random item by seed (day).
SELECT * FROM article ORDER BY rand("20190131") # date(Ymd)
Order by array
Get items from array, then order by field.
SELECT * FROM documents
WHERE id IN (3, 7, 5) ORDER BY FIELD (id, 3, 7, 5)
➥ Questions
