group by range

建立测试表

testdb=# CREATE TEMP TABLE team (

id serial,

name text,

birth_year integer,

salary integer

);

插入记录

testdb=# INSERT INTO team (name, birth_year, salary)

VALUES ('Gabriel', 1970, 44000),

('Tom', 1972, 36000),

('Bill', 1978, 39500),

('Bob', 1980, 29000),

('Roger', 1976, 26800),

('Lucas', 1965, 56900),

('Jerome', 1984, 33500),

('Andrew', 1992, 41600),

('John', 1991, 40000),

('Paul', 1964, 39400),

('Richard', 1986, 23000),

('Joseph', 1988, 87000),

('Jason', 1990, 55000);

查询结果

testdb=# WITH series AS ( 

SELECT generate_series(1950, 2000, 10) AS time_start -- 1950 = min, 2010 = max, 10 = 10 year interval

), range AS (

SELECT time_start, (time_start + 9) AS time_end FROM series -- 9 = interval (10 years) minus 1

)

SELECT time_start, time_end,

(SELECT count(*) FROM team WHERE birth_year BETWEEN time_start AND time_end) as team_members,

round((SELECT AVG(salary) FROM team WHERE birth_year BETWEEN time_start AND time_end), 2) as salary_avg,

(SELECT MIN(salary) FROM team WHERE birth_year BETWEEN time_start AND time_end) as salary_min,

(SELECT MAX(salary) FROM team WHERE birth_year BETWEEN time_start AND time_end) as salary_max

FROM range;

输出结果：

time_start | time_end | team_members | salary_avg | salary_min | salary_max 

------------+----------+--------------+------------+------------+------------

1950 | 1959 | 0 | | | 

1960 | 1969 | 2 | 48150.00 | 39400 | 56900

1970 | 1979 | 4 | 36575.00 | 26800 | 44000

1980 | 1989 | 4 | 43125.00 | 23000 | 87000

1990 | 1999 | 3 | 45533.33 | 40000 | 55000

2000 | 2009 | 0 | | | 

(6 rows)

testdb=#

本文转自 pgmia 51CTO博客，原文链接:http://blog.51cto.com/heyiyi/2070561