select id,visit_date,people from( select *, lag(people,1) over(order by id)l1, lag(people,2)over(order by id) l2, lead(peopl...

select round( ifnull( 1/(count( distinct f1.sender_id,f1.send_to_id) /count(distinct r1.requester_id,r1...

select class from courses group by 1 having count(distinct student)>=5

程序员不能跑着写代码，工作量一多，就要久坐。遇到难写的代码，大脑就要消耗很多能量，为了维持大脑运转，就需要摄入含糖量高的甜食，快速恢复血糖。再加上赶进度，加班熬夜吃夜宵，更加促进了体重的增长。...

select c.country_name, case when avg(w.weather_state)<=15 then "Cold" when avg(w.weather_state)<25 then "Warm" else "Hot" end weather_type...

select name,population,area from world where area>3000000 or population>25000000

select customer_number from orders group by 1 order by count(*) desclimit 0,1

select round(sum(tiv_2016),2) tiv_2016 from (select *,count(*) over(partition by tiv_2015) a1,count(*) over(partition by lat,lon) a2 from insurance) as...

select name from customer where referee_id <>2 or isnull(referee_id)

select dept_name,count(student_id) student_number from department d left join student s on d.dept_id=s.dept_id group by dept_name order by 2 d...