Exercise 4：571.Find Median Given Frequency of Numbers

1 Description

TThe Numbers table keeps the value of number and its frequency.

+----------+-------------+
|  Number  |  Frequency  |
+----------+-------------|
|  0       |  7          |
|  1       |  1          |
|  2       |  3          |
|  3       |  1          |
+----------+-------------+

In this table, the numbers are 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 2, 3, so the median is (0 + 0) / 2 = 0.

+--------+
| median |
+--------|
| 0.0000 |
+--------+

Write a query to find the median of all numbers and name the result as median.

2 Create Table and insert into values

create table if not exists leetcode.ex_571_number
(
 number int, 
 frequency int
)  stored as orc ;

INSERT INTO table leetcode.ex_571_number  VALUES
('0' , '7' ),
('1' , '1' ),
('2' , '3' ),
('3' , '1' )