SQL & PL/SQL :: Results Of Query To Be Displayed In One Line

I have this query:

select distinct event_number from events_total WHERE event_id = 16395493
minus
select distinct event_number from event_details_ford WHERE event_id = 16395493

result of which is :
6L2Z-7861693-AAC
6L2Z-7862187-CAC

i want to put this in dynamic sql where clause :

where event_number in ('6L2Z-7861693-AAC','6L2Z-7862187-CAC'). and if the result of the query is only one number, then where event_number in (6L2Z-7861693-AAC) result of the query can be NULL also. but i think i can use IF condition for "SELECT ..WHERE event_number in " query

so how can i put the results of query in one line, so that i can use it in where clause.