Postgres 12

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select version();


version


PostgreSQL 12.12 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-10), 64-bit



SELECT 1


create table t(person_id int, age int)

CREATE TABLE


insert into t
select 21352471,    59 union all
select 22157363,    51 union all
select 22741394,    75 union all
select 22764902,    27 union all
select 22771872,    62 

INSERT 0 5


select concat(
        (age/10)*10 
       ,'-'
       ,(age/10)*10+10
        )as age_bracket
      ,count(person_id) as frequency
 from t
group by concat(
        (age/10)*10 
       ,'-'
       ,(age/10)*10+10
        )
order by 1  


age_bracket
frequency


20-30
1

50-60
2

60-70
1

70-80
1



SELECT 4