Re: clarification on chaining of set operations

PG Doc comments form <noreply@postgresql.org> writes:
> Regarding section 7.4 of the documentation.  I was curious about the
> behavior when combining different set operations in one query, e.g, 
> query1 op1 query2 op2 query3;
> where op1 and op2 are one of UNION, INTERSECT, EXCEPT.

> The documentation suggests that this is equivalent to 
> (query1 op1 query2) op2 query3;
> but only states it for the case when op1 = op2 = UNION.

The SELECT reference page explains that INTERSECT binds more tightly
than UNION or EXCEPT.  I think it's an oversight that section 7.4
doesn't mention that.

            regards, tom lane