Random query of databases

SELECT * FROM 'table' WHERE id> = (SELECT floor (RAND () * (select max (id) FROM 'table '))) order by id LIMIT 1; finally, complete the statement and add the MIN (id) judgment. At the beginning of the test, because I did not add the MIN (id) Judgment, half of the time is always the first few rows in the table. The complete query statement is: SELECT * FROM 'table' WHERE id> = (SELECT floor (RAND () * (select max (id) FROM 'table ') -(select min (id) FROM 'table') + (select min (id) FROM 'table') order by id LIMIT 1; SELECT * FROM 'table' AS t1 JOIN (select round (RAND () * (select max (id) FROM 'table')-(select min (id) FROM 'table') + (select min (id) FROM 'table') AS id) AS t2 WHERE t1.id> = t2.id order by t1.id LIMIT 1; finally, the two statements are queried for 10 times in php respectively. The former takes 0.147433 seconds, and the latter takes 0.015130 seconds. It seems that the JOIN syntax is much more efficient than using functions directly in the WHERE clause.