Help with a tricky sql

Question

** Consider the following table; we'll name this 'entities' for
the following discussion.
ENTITY FORM DEPTH EQUIV SOURCE
100012802307W502 DVNU 1458 14399 GOVT
100012802307W502 DVNU 1458 14399 IPL
100012802307W502 PLSR 1455 14399 GOVT
100012802307W502 PLSR 4238 14399 wayrig
100012802307W502 PLSR 4450.4 14399 GOVT
100012802307W502 PLSR 4788.3 14399 GOVT
101070403227W300 BGVL 800 14399 GOVT
101070403227W300 DVNU 855.3 14390 IPL
101070403227W300 DVNU 855.6 14399 GOVT
** The goal
For each unique ID (only 2 in the above example table: 100012802307W502
and 101070403227W300)
We need to get a single 'formation pick'.
Without going into details, 'formation pick' is an industry term and
in our example, a formation pick is identified by the FORM attribute.
** The Problem
Given the above, the question which I need to answer is
for each unique ENTITY, I want to get the PLSR formation pick.
If for any ENTITY, there is not a PLSR pick, but there is
an EQUIVALENT pick then for that ENTITY, we want that equivalent pick
(in our example above, all FORM which have the same EQUIV value are
considered equivalent; thus for 100012802307W502, there are PLSR picks
while for 101070403227W300, there are not but there are equivalent
picks (DVNU and BGVL)
The picks are to be selected based on a priority
top priority is given to SOURCE wayrig
If a given pick does not have a wayrig, SOURCE, then accept IPL
Finally, if neither the wayrig, or IPL SOURCE are available,
accept the GOVT pick
Thus, for 100012802307W502, where there are multiple PLSR picks, we
want the one with the highest available priority
(the 100012802307W502 PLSR 4238 14399 wayrig)
row
For 101070403227W300, which does not have a PLSR pick, we need to consider
the qualifying equivalent picks and the highest applicable priority for
these picks is where SOURCE = GOVT -> rows
101070403227W300 BGVL 800 14399 GOVT
101070403227W300 DVNU 855.6 14399 GOVT
Thus, the final condition that
should there be 2 or more picks whose priority is the same, then we
want the one with the shallowest DEPTH
row
101070403227W300 BGVL 800 14399 GOVT
Thus the desired final results
ENTITY FORM DEPTH EQUIV SOURCE
100012802307W502 PLSR 4238 14399 wayrig
101070403227W300 BGVL 800 14399 GOVT
** Constraints
It is most desireable to achieve this without having to create
physical tables and/or views as the query(ies) must run against
a public database where users do not have create table privileges.
If anyone has solutions that include physical tables, please submit
these anyways as they may help us devise the ultimate approach that
we are seeking.
More info (in case this is helpful)
I have been working on this and variations of this problem for
a little while.
Here is a query that was submitted to me via this discussion group
sometime ago on a similar problem
select ENTITY, FORM, MIN(DECODE ( SOURCE,'wayrig',1,'IPL',2, 3)) PICK_PRIORITY
from entities
where EQUIV = '14399'
GROUP BY ENTITY, FORM
ENTITY FORM PICK_PRIORITY
100012802307W502 DVNU 2
100012802307W502 PLSR 1
101070403227W300 BGVL 3
101070403227W300 DVNU 3
as you can see, the above query gets me partially where I need to go.
Unfortunately, I have not been able to adapt the above query in such a
way as to get the rest of the information related to the selected ENTITY;
that is, the DEPTH, EQUIV, and SOURCE values are not present in the
selected data.
And of course, the above is only a piece of the puzzle as it does not
get me a single row per selected ENTITY.
Thanks for your consideration
null

Answer 1

"bounoe",
I am a little bit confused, because what you are asking for and the sample result seem to be in slight conflict. What you ask for does not require that equiv = '14399', but your results seem to.
So, if equiv must equal '14399', then
SELECT DISTINCT entity, form, depth, equiv, source
FROM entities
WHERE equiv = '14399'
AND (entity,
DECODE(form,'PLSR',1,2),
depth,
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)) IN
(SELECT entity,
DECODE(form,'PLSR',1,2),
MIN(depth),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)
FROM entities
WHERE equiv = '14399'
AND (entity,
DECODE(form,'PLSR',1,2),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)) IN
(SELECT entity,
DECODE(form,'PLSR',1,2),
MIN(DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4))
FROM entities
WHERE equiv = '14399'
AND (entity,DECODE(form,'PLSR',1,2)) IN
(SELECT entity,
MIN(DECODE(form,'PLSR',1,2))
FROM entities
WHERE equiv = '14399'
GROUP BY entity)
GROUP BY entity,DECODE(form,'PLSR',1,2))
GROUP BY entity,
DECODE(form,'PLSR',1,2),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4));
ENTITY FORM DEPTH EQUIV SOURCE
100012802307W502 PLSR 4238 14399 wayrig
101070403227W300 BGVL 800 14399 GOVT
If equiv need not equal '14399':
SELECT DISTINCT entity, form, depth, equiv, source
FROM entities
WHERE (entity,
DECODE(form,'PLSR',1,2),
depth,
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)) IN
(SELECT entity,
DECODE(form,'PLSR',1,2),
MIN(depth),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)
FROM entities
WHERE (entity,
DECODE(form,'PLSR',1,2),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4)) IN
(SELECT entity,
DECODE(form,'PLSR',1,2),
MIN(DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4))
FROM entities
WHERE (entity,DECODE(form,'PLSR',1,2)) IN
(SELECT entity,
MIN(DECODE(form,'PLSR',1,2))
FROM entities
GROUP BY entity)
GROUP BY entity,DECODE(form,'PLSR',1,2))
GROUP BY entity,
DECODE(form,'PLSR',1,2),
DECODE(source,'wayrig',1,'IPL',2,'GOVT',3,4));
ENTITY FORM DEPTH EQUIV SOURCE
100012802307W502 PLSR 4238 14399 wayrig
101070403227W300 DVNU 855 14390 IPL
If neither of these is exactly what you need, please let me know.
Barbara
null