Summing Distinct values - snowflake-cloud-data-platform

Question

I have this code, and I want to sum only the distinct values from the "TARGET_QUIKPLANSur.PLAN" table. But I don't know what I am doing wrong.
SELECT Distinct TARGET_QUIKPLANSur.PLAN, TARGET_QUIKPLANSur.FORM, Sum(TARGET_NEWQUIKVALFSurDec.MANNLZD) AS PREMIUM
from TARGET_QUIKPLANSur Left JOIN TARGET_NEWQUIKVALFSurDec ON TARGET_QUIKPLANSur.PLAN=TARGET_NEWQUIKVALFSurDec.NPLAN
GROUP BY TARGET_QUIKPLANSur.FORM, TARGET_QUIKPLANSur.PLAN
HAVING(((TARGET_QUIKPLANSur.FORM)='LN-5350') and TARGET_QUIKPLANSur.PLAN = 'N06000')

Answer 1

How about this?
SELECT PLAN, FORM, SUM(MANNLZD) FROM
(SELECT Distinct TARGET_QUIKPLANSur.PLAN, TARGET_QUIKPLANSur.FORM, TARGET_NEWQUIKVALFSurDec.MANNLZD AS PREMIUM
from TARGET_QUIKPLANSur Left JOIN TARGET_NEWQUIKVALFSurDec ON ARGET_QUIKPLANSur.PLAN=TARGET_NEWQUIKVALFSurDec.NPLAN )
GROUP BY FORM, PLAN
HAVING((FORM='LN-5350') and PLAN = 'N06000')
Filtering before grouping would be better:
SELECT PLAN, FORM, SUM(MANNLZD) FROM
(SELECT Distinct TARGET_QUIKPLANSur.PLAN, TARGET_QUIKPLANSur.FORM, TARGET_NEWQUIKVALFSurDec.MANNLZD AS PREMIUM
from TARGET_QUIKPLANSur Left JOIN TARGET_NEWQUIKVALFSurDec ON ARGET_QUIKPLANSur.PLAN=TARGET_NEWQUIKVALFSurDec.NPLAN
WHERE FORM='LN-5350' and PLAN = 'N06000')
GROUP BY FORM, PLAN;

Answer 2

we formatting your SQL so it's more readable:
SELECT DISTINCT q.plan
,q.form
,SUM(n.mannlzd) AS premium
FROM target_quikplansur AS q
LEFT JOIN target_newquikvalfsurdec AS n
ON q.plan = n.nplan
GROUP BY q.form, q.plan
HAVING q.form='LN-5350' and q.plan = 'N06000'
One guess to what
I want to sum only the distinct values from the "TARGET_QUIKPLANSur.PLAN" table"
means, could be you have many rows in TARGET_QUIKPLANSur and you only want them to join once to your target_newquikvalfsurdec table, thus currently if you had two rows in target_newquikvalfsurdec with value 10 you want 20 as you answer, but if you have 2+ duplicate rows in TARGET_QUIKPLANSur you are getting something like 40
In that case you should deduplicate your TARGET_QUIKPLANSur values before joining to them
SELECT q.plan
,q.form
,SUM(n.mannlzd) AS premium
FOM (
SELECT DISTINCT plan, form
FROM target_quikplansur
) AS q
LEFT JOIN target_newquikvalfsurdec AS n
ON q.plan = n.nplan
WHERE q.form='LN-5350' and q.plan = 'N06000'
Another way your question:
I want to sum only the distinct values from the "TARGET_QUIKPLANSur.PLAN" table"
could be read, is you have some rows with duplicates and you only want the rows with no duplicates. Thus for the data
form plan
'LN-5350', 'N06000'
'LN-5350', 'N06000'
'LN-5350', 'N06001'
'LN-5350', 'N06002'
you want only the rows 'N06001', & 'N06002' as they don't have duplicates. I suspect this is not what your wanting, but if it was you would use COUNT of the rows, and HAVING to filter like.
SELECT q.plan
,q.form
,SUM(n.mannlzd) AS premium
FOM (
SELECT plan, form
FROM target_quikplansur
GROUP BY 1,2
HAVING COUNT(*) = 1
) AS q
LEFT JOIN target_newquikvalfsurdec AS n
ON q.plan = n.nplan
WHERE q.form='LN-5350' and q.plan = 'N06000'
OR another way to look at it, would be that you want the first row based on some other value, thus with:
form plan other
'LN-5350', 'N06000' 1
'LN-5350', 'N06000' 2
'LN-5350', 'N06001' 1
'LN-5350', 'N06002' 1
you might want the highest other value thus with a QUALIFY and ROW_NUMBER you can filter the values
SELECT q.plan
,q.form
,SUM(n.mannlzd) AS premium
FOM (
SELECT plan, form
FROM target_quikplansur
QUALIFY ROW_NUMBER() OVER (PARTITION BY plan, form ORDER BY other DESC) = 1
) AS q
LEFT JOIN target_newquikvalfsurdec AS n
ON q.plan = n.nplan
WHERE q.form='LN-5350' and q.plan = 'N06000'
to limit to these rows:
'LN-5350', 'N06000' 2
'LN-5350', 'N06001' 1
'LN-5350', 'N06002' 1