Oracle 11g Release 2

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create table ep_pay_stubs(display_date date)

insert into ep_pay_stubs select to_date('01/01/2019','MM/DD/YYYY') from dual connect by level<=50000
50000 rows affected

with cte as (
	select
	xmlelement("root",
		xmlagg(
			xmltype(
				dbms_xmlgen.getxml('select to_char(display_date, ''YYYY-MON'') as year_mon, count(*) month_count from ' ||
					owner || '.' || table_name ||
					' WHERE display_date BETWEEN to_date(''01/01/2019'',''MM/DD/YYYY'') AND TO_DATE(''10/31/2019 23:59:59'',''MM/DD/YYYY HH24:MI:SS'')' ||
					' group by to_char(display_date, ''YYYY-MON'')'
				)
			)
		)
	) myxml
	from all_tables
	where table_name = 'EP_PAY_STUBS' 
)
select year_month, sum(month_count)
from cte, xmltable(
			'/root/ROWSET/ROW'
			passing myxml
			columns
				year_month			varchar2(8)		path 'YEAR_MON',
				month_count			number			path 'MONTH_COUNT'
		)
group by year_month
order by to_date(year_month,'YYYY-MON')
/



YEAR_MONTH
SUM(MONTH_COUNT)


2019-JAN
50000