Hi Andrew,
>
> See the algrebra expressions for the two queries above. The FILTER is in
> different places - inside and outside the UNION.
Yes. I understand.
> {} means, very loosely, evaluate this part and use the results.
I see.
> In the algebra is like function call : evaluate the arguments then call the
> operation with the results of sub-evaluation.
>
> Just as (1+2) * (3+4) becomes 3 * 7 and hence is 21.
>
> int x = 8
> sqrt(x+1)
>
> is a function call to sqrt(9), not passing "x+1" into sqrt.
thanks for the clarification.
--
Gary Warren King, metabang.com
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