Обсуждение: UNION help

Is there anyway to tell if the records in a union came from the 1st query or the second?
Can I modify the individual queries to let me know this?

You could modify the queries and then do a union all... but then you may
see the same result from each part of the union. Which may or may not be a
problem for you.

On Thu, 17 May 2007, Robert James wrote:

> Is there anyway to tell if the records in a union came from the 1st query or
> the second?
> Can I modify the individual queries to let me know this?
>

Robert James wrote:
> Is there anyway to tell if the records in a union came from the 1st
> query or the second?
> Can I modify the individual queries to let me know this?
You can do something like:

select 'set1' as identifier, field1, field2 from table1
union
select 'set2', field1, field2 from table2