How to prioritize a record In sql server? - sql

Question

I want to try to write a query. I need to take the Targetvalue from #MetricTargets table for the MetricID's which are there in #Metrics.
{
CREATE TABLE #Metrics(
MetricId BiginT,
AccountId Bigint,
CountryId Bigint
)
INSERT INTO #Metrics(MetricId,AccountId,CountryId)select 8253,3,105
Create table #MetricTargets(
AccountId BIGINT,
MetricId BIGINT,
TargetValue BIGINT,
Countryid BIGINT
)
INSERT INTO #MetricTargets(AccountId,TargetValue,MetricId,Countryid)SELECT 105,100,3,8253
INSERT INTO #MetricTargets(AccountId,TargetValue,MetricId,Countryid)SELECT -1,80,3,8253
INSERT INTO #MetricTargets(AccountId,TargetValue,MetricId,Countryid)SELECT 105,99,-1,8253
}
CountryId=-1 and AccountId =-1 represents for all Countries and Accounts
So I want to retrieve Targetvalue for a metricId if the AccountId and CountryId is given in #MetricTargets table in first Priority , AccountId =Something and countryId = -1 is 2 nd priority,ACcountId=-1 and CountryId= SomeThing then 3rd priority and AccountId =-1 and CountryId=-1 then last priority.
I wrote the below query but it is giving all records.
select M.TargetValue from #Metrics S
LEFT JOIN #MetricsTargets M
ON M.MetricId = S.MetricId AND (S.AccountId+M.AccountId<S.AccountId or S.AccountId = M.AccountId)
AND (S.CountryId+M.CountryId<S.CountryId or S.CountryId=M.CountryId)

Answer 1

You seem to want matching with -1 as a wildcard of lower priority. I'm pretty sure a lateral join does what you want:
select . . .
from #Metrics m OUTER APPLY
(select top (1) mt.*
from #MetricsTargets mt
where mt.MetricId = m.MetricId and
m.account_id in (mt.account_id, -1) and
m.country_id in (mt.country_id, -1)
order by (case when mt.account_id = m.account_id and mt.country_id = m.country_id
then 1
when mt.account_id = m.account_id and mt.country_id = -1
then 2
when mt.account_id = -1 and mt.country_id = m.country_id
then 3
when mt.account_id = -1 and mt.country_id = -1
then 4
end)
) mt