how to show month if no sales

Hi All,

Working in OPM

Version 12.2.10

how to show month if no sales in current year,

for example

in April there is sales but not in may and again june there is sales like wise

now what i am facing the problem is last year there is sales for May month but in current year there is no sales for May Month so it is skipping not showing data completely, so the report history sales not showing correct data,

I need some help, if no sales, show month

sample query

select distinct customer_name, to_char(trx_date,'Month') aa