finding unique record using min and max in same query from several criteria - sql

Question

I have a common table expression with the following fields
product.identifier, ingredient.identifier, ingredient.cost,
ingredient.isActive, ingredient.isPrimary
I'm trying to find a record based off the following criteria among multiple records
if isActive = 1 and isPrimary = 1, choose that record
if the record with isPrimary = 1 but isActive = 0, choose the record with the highest/max cost where isPrimary = 0 and isActive = 1
if all records from step 2 have the same cost, choose the oldest/min record based off ingredient.Identifier
the logic to find these on their own is simple but combining the logic into one clause is not working as expected. here is the expected output I'm trying to match along with the incorrect SQL
product ingredient cost isActive isPrimary isChosenRecord
-- isActive and isPrimary example
1 10 1.00 1 1 yes
1 11 1.10 1 0 no
2 20 2.00 1 1 yes
2 22 2.15 1 0 no
-- primary record is inactive, choose max cost record
3 30 3.00 0 1 no
3 31 3.10 1 0 no
3 32 3.20 1 0 yes
4 40 4.00 0 1 no
4 41 4.10 1 0 no
4 42 4.20 1 0 yes
-- primary record is inactive, all records have same cost, choose oldest record
5 50 5.00 0 1 no
5 51 5.00 1 0 yes
5 52 5.00 1 0 no
6 60 6.00 0 1 no
6 61 6.00 1 0 yes
6 62 6.00 1 0 no
; with [ActiveRecordsCTE] as
(
select
ProductIdentifier = p.Identifier,
IngredientIdentifier = i.Identifier,
i.Cost, i.isActive, i.isPrimary
from Product p
inner join Ingredient i on i.Identifier = p.Identifier
where i.isActive = 1
),
[CalculatedPrimaryRecords] AS
(
SELECT
r.ProductIdentifier,
r.IngredientIdentifier
FROM ActiveRecordsCTE r
WHERE r.IsPrimary = 1
UNION
-- get the oldest records
SELECT
r.ProductIdentifier,
IngredientIdentifier = min(r.IngredientIdentifier)
FROM
(
-- get most expensive record by cost
SELECT
r.ProductIdentifier,
r.IngredientIdentifier
FROM ActiveRecordsCTE a
CROSS APPLY
(
-- get most expensive record per product
SELECT
r.ProductIdentifier
,MaxAssetValue = MAX(r.Cost)
FROM ActiveRecordsCTE b
WHERE b.IsPrimary = a.IsPrimary
AND a.ProductIdentifier = b.ProductIdentifier
AND a.IngredientIdentifier = b.IngredientIdentifier
GROUP BY b.ProductIdentifier
) ca
WHERE a.IsPrimary = 0
-- exclude records that are included in the statement above
AND a.ProductIdentifier NOT IN
(
SELECT ProductIdentifier
FROM ActiveRecordsCTE
WHERE IsPrimary = 1
)
) sub
GROUP BY sub.ProductIdentifier
)
select * from [CalculatedPrimaryRecords]

Answer 1

Use row_number() for this type of prioritization:
with cte as ( . . . )
select t.*
from (select cte.*,
row_number() over (partition by product
order by (case when isActive = 1 and isPrimary = 1 then 1
when isActive = 0 and isPrimary = 1 then 2
else 3
end),
cost desc,
identifier asc
) as seqnum
from cte
) t
where seqnum = 1;
This makes some assumptions that seem consistent with the question:
isActive and isPrimary only take on the values 0 and 1.
If no records have isPrimary = 1, then you still want a record. (If not, these can easily be filtered out.)
identifier is not defined in your sample data.
EDIT:
If you wanted to be fancy, you could use top (1) with ties:
select top (1) with ties cte.*
from cte
order by row_number() over (partition by product
order by (case when isActive = 1 and isPrimary = 1 then 1
when isActive = 0 and isPrimary = 1 then 2
else 3
end),
cost desc,
identifier asc
);
I actually prefer the row_number() solution because I'm not sure what to do in the case that isPrimary = 0 and it is easier to add logic for that solution to filter out those records.