Altering a QUALIFY with an additional criterion - snowflake-cloud-data-platform

Question

In Snowflake I have this original query which, for a given consumer_ID, produces a list of unique store IDs.
SELECT
t.consumer_id
, t.business_id
, t.store_id
, t.campaign_id
FROM campaigns_mini AS t
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.store_id ORDER BY t.campaign_id) = 1
The original purpose was to provide a list that does not duplicate store_id for a given consumer_id. Suppose now I also need to ensure this list does not duplicate business_id as well for a given consumer_ID. Is there an easy way to modify the above?

Answer 1

SELECT
t.consumer_id
, t.business_id
, t.store_id
, t.campaign_id
FROM campaigns_mini AS t
QUALIFY ROW_NUMBER() OVER
(PARTITION BY t.consumer_id
,t.store_id
,t.business_id
ORDER BY t.campaign_id) = 1
The partition by clause forms windows by the combination of all the expressions in the clause.
This will deduplicate by the combination of consumer_id, store_id, and business_id. If this is not what you need, please update with sample input and output to clarify.

Answer 2

So if I make up some data:
WITH campaigns_mini(consumer_id, business_id, store_id, campaign_id) as (
select * from values
(1,10,100,1000),
(1,10,100,1001),
(1,10,101,1002),
(2,20,200,2000)
)
and use your exist SQL
SELECT
t.consumer_id
,t.business_id
,t.store_id
,t.campaign_id
FROM campaigns_mini AS t
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.store_id ORDER BY t.campaign_id) = 1
I get
CONSUMER_ID
BUSINESS_ID
STORE_ID
CAMPAIGN_ID
1
10
101
1002
1
10
100
1000
2
20
200
2000
we get the Store not repeated for the Consumer, but as you note you don't want the business repeated ether..
If we change to using business_id instead of store_id we see we get less rows:
SELECT
t.consumer_id
,t.business_id
,t.store_id
,t.campaign_id
FROM campaigns_mini AS t
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.business_id ORDER BY t.campaign_id) = 1
ORDER BY 1;
CONSUMER_ID
BUSINESS_ID
STORE_ID
CAMPAIGN_ID
1
10
100
1000
2
20
200
2000
So if we want "no repeating business_id AND no repeating stores" using the Qualify Greg's has proposed will not help, as we are keeping the first for the distinct set of consumer,business, & store:
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.business_id, t.store_id ORDER BY t.campaign_id) = 1
which gives:
CONSUMER_ID |BUSINESS_ID |STORE_ID |CAMPAIGN_ID
1 |10 |100 |1000
1 |10 |101 |1002
2 |20 |200 |2000
So the next thing is to think why not keep the only the first of the two sets:
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.store_id ORDER BY t.campaign_id) = 1
AND ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.business_id ORDER BY t.campaign_id) = 1
which for this data works!
CONSUMER_ID
BUSINESS_ID
STORE_ID
CAMPAIGN_ID
1
10
100
1000
2
20
200
2000
but then for this data:
WITH campaigns_mini(consumer_id, business_id, store_id, campaign_id) as (
select * from values
(1,10,100,1000),
(1,10,101,1001),
(1,20,101,1002)
)
there is only one row with business 20, for store 101, but the first 101 store is on campaign 1001, so both those rows are discarded.
CONSUMER_ID
BUSINESS_ID
STORE_ID
CAMPAIGN_ID
1
10
100
1000
So if we use two layers to do the prune, for this data:
select * from (
SELECT
t.consumer_id
,t.business_id
,t.store_id
,t.campaign_id
FROM campaigns_mini AS t
QUALIFY ROW_NUMBER() OVER (PARTITION BY t.consumer_id, t.business_id ORDER BY t.campaign_id) = 1
)
QUALIFY ROW_NUMBER() OVER (PARTITION BY consumer_id, store_id ORDER BY campaign_id) = 1
works:
CONSUMER_ID
BUSINESS_ID
STORE_ID
CAMPAIGN_ID
1
10
100
1000
1
20
101
1002
but if your flip those orders of QUALIFY you are back to just one row..
so as a general problem it cannot be safely solve for all data cases with this pattern...