MySQL 8.0

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create table my_table as

select 1 as id, date('2020-03-02') as startdate, date('2020-03-02') as enddate union all

select 2, date('2020-04-02') as startdate, date('2020-04-02') as enddate union all

select 3, date('2020-04-02') as startdate, date('2020-05-02') as enddate union all

select 4, date('2020-04-02') as startdate, date('2020-05-02') as enddate union all

select 5, date('2020-05-02') as startdate, date('2020-06-02') as enddate union all

select 6, date('2020-05-02') as startdate, date('2020-06-02') as enddate union all

select 7, date('2020-06-02') as startdate, date('2020-07-02') as enddate

Records: 7  Duplicates: 0  Warnings: 0

Select ifnull(Tb1.mn,Tb2.mn) As mn, ifnull(count_mn_start,0) As count_mn_start, ifnull(count_mn_end,0) As count_mn_end

from

(Select Month(StartDate) as mn, count(id) as count_mn_start

from

my_table

Group by Month(StartDate))Tb1

left Join (Select Month(EndDate) as mn, count(id) as count_mn_end

from my_table

Group by Month(EndDate)) Tb2

on Tb1.mn = Tb2.mn

UNION

Select ifnull(Tb1.mn,Tb2.mn) As mn, ifnull(count_mn_start,0) As count_mn_start, ifnull(count_mn_end,0) As count_mn_end

from

(Select Month(StartDate) as mn, count(id) as count_mn_start

from

my_table

Group by Month(StartDate))Tb1

Right Join (Select Month(EndDate) as mn, count(id) as count_mn_end

from my_table

Group by Month(EndDate)) Tb2

on Tb1.mn = Tb2.mn;