比较Oracle SQL中两个字段的值

Question

I have this statement in Oracle:

select agnt_name,
       exporter_name
from
(
  select agnt_name,
         exporter_name
  from Exporters
  union all
  select agnt_name,
         exporter_name
  from agents
)

now if I add this condition: WHERE agnt_name = exporter_name

My question is: Will the query compare the values in both fields & if they equal it'll show the records? Or will this condition be like a join condition?

Answer 1

You have no join in your query -- not even an implicit join . Hence, adding the condition will just compare the values in the two columns in the same row.