MySql Date NTiles, MySQL

Language: Layout:

#mysql 5.7.12
#please drop objects you've created at the end of the script 
#or check for their existance before creating

drop table if exists p;

create table p (id int, date date);

insert into p values (1,'2014-10-01'),
(2,'2014-11-01'),
(3,'2015-02-01'),
(2,'2015-04-15'),
(4, '2015-08-15'),
(3,'2015-10-01'),
(2,'2016-01-01')
;

select unix_timestamp(min(date)) into @start from p;
select unix_timestamp(max(date)) into @end from p;
Set @25 = 0.25 *(@end - @start)+@start;
Set @50 = 0.50 *(@end - @start)+@start;
Set @75 = 0.75 *(@end - @start)+@start;

select 
case when unix_timestamp(date)>@75 then 4
when unix_timestamp(date)>@50 then 3
when unix_timestamp(date)>@25 then 2
else 1 end as Quartile, 
concat(round(count(id)/(select count(*) from p)*100,2),'%') as Percentage
,case when unix_timestamp(date)>@75 then CONCAT(DATE_FORMAT(FROM_UNIXTIME(@75),'%Y-%m-%d'),' - ',DATE_FORMAT(FROM_UNIXTIME(@end),'%Y-%m-%d'))
when unix_timestamp(date)>@50 then CONCAT(DATE_FORMAT(FROM_UNIXTIME(@50),'%Y-%m-%d'),' - ',DATE_FORMAT(FROM_UNIXTIME(@75),'%Y-%m-%d'))
when unix_timestamp(date)>@25 then CONCAT(DATE_FORMAT(FROM_UNIXTIME(@25),'%Y-%m-%d'),' - ',DATE_FORMAT(FROM_UNIXTIME(@50),'%Y-%m-%d'))
else CONCAT(DATE_FORMAT(FROM_UNIXTIME(@start),'%Y-%m-%d'),' - ',DATE_FORMAT(FROM_UNIXTIME(@25),'%Y-%m-%d')) end as Date_Range
from p group by Quartile;


absolute service time: 0,35 sec