I was thinking about subselects, and how to attach the two queries.
What if the subquery makes a range table entry in the outer query, and
the query is set up like the UNION queries where we put the scans in a
row, but in the case we put them over/under each other.
And we push a temp table into the catalog cache that represents the
result of the subquery, then we could join to it in the outer query as
though it was a real table.
Also, can't we do the correlated subqueries by adding the proper
target/output columns to the subquery, and have the outer query
reference those columns in the subquery range table entry.
Maybe I can write up a sample of this? Vadim, would this help? Is this
the point we are stuck at?
--
Bruce Momjian
maillist@candle.pha.pa.us