[SQL] Query Count, Min, Max, Mean, Median and Quartile in one statement

query_statistics.sql

SELECT
	`count` AS `count`,
	MIN(`value`) AS `min`,
	MAX(`value`) AS `max`,
	AVG(`value`) AS `mean`,
	AVG(CASE WHEN ABS(`rank`-`count`*.25 + .5)<=.5 THEN `value` ELSE NULL END) AS q1,
	AVG(CASE WHEN ABS(`rank`-`count`*.5 + .5)<=.5 THEN `value` ELSE NULL END) AS q2,
	AVG(CASE WHEN ABS(`rank`-`count`*.75 + .5)<=.5 THEN `value` ELSE NULL END) AS q3
FROM
(
	SELECT  `value`, @i_rank:=@i_rank+1 AS `rank`
	FROM (
		-- SQL don't allow order in subquery only if it has limit (tested in MariaDB)
		SELECT <your_column> AS `value` FROM <your_table> ORDER BY 1 LIMIT 100000000
	) AS t_rank_value, (SELECT @i_rank:=0) AS t_rank_rank
) AS `t_rank`,
(
	SELECT COUNT(*) AS `count` FROM <your_table>
) AS `t_count`