to_number question 2004-07-15 - By Jonathan Gennick
Thursday, July 15, 2004, 9:09:02 AM, Wolfgang Breitling (breitliw@(protected)) wrote:
WB > As I tried to explain in my post, the optimizer deals with basic relational
WB > operations - projection, filter, and join. If you visualize a table as a 2-
WB > dimensional array, then projection limits the total set veryically, to certain
WB > columns, and a filter limits the set horizontally, to a certain set of row, and
WB > a join cobines two sets. Relational theory guarantees that these operations are
WB > commutative, i.e. the order does not matter. The relational engine is
WB > explicitly allowed to reorder them as needed.
I respectfully disagree in this case. We 're talking about a
query with a subquery. Here 's Stephen 's query again:
select /*+ NO_MERGE(Z) NO_PUSH_PRED(Z) PUSH_SUBQ(Z) */
distinct nbr_cc_fop_name into v_fop
from (select nbr_cc_fop_name, nbr_cc_fop_high, nbr_cc_fop_low
from nbr_cc
where nbr_cc_fop_name in ( 'AX ', 'MC ', 'VI ', 'DS ')) Z
where to_number(trim(substr(p_corigid,1,20))) between
to_number(trim(nbr_cc_no_low))
and to_number(trim(nbr_cc_no_high));
The target "table " for the outer query is that set of rows
returned from the inner query. Thus, the outer query *must*
consider only those rows. It 's a fault, in my current
opinion, for the outer query to look at any row not returned
by the inner query.
Best regards,
Jonathan Gennick --- Brighten the corner where you are
http://Gennick.com * 906.387.1698 * mailto:jonathan@(protected)
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