SQL Server : stored procedure many-to-many table query - sql

Question

I have 3 tables Campaign, Mall, MallCampaign (many-to-many) and want to order nearest campaigns which are available in one or more malls.
In the first query; I am eligible for reaching the campaigns' distance which are available in different malls. But need to do it for all campaigns not only one (Id=79). I couldn't manage to do it with JOIN.
SELECT
m.MallId,
ROUND(#geo1.STDistance(geography::Point(m.MallLatitude, m.MallLongitude, 4326))/1000,1) AS Distance
FROM
MallCampaign mc
INNER JOIN
Mall m ON m.MallId = mc.MallId
WHERE
m.IsActive != 0 AND mc.CampaignId = 79
ORDER BY
Distance
SELECT
ca.CampaignId, ca.CampaignTitle
FROM
Campaign ca

Answer 1

Does this do what you want? It sorts by campaign id first and then by distance:
SELECT mc.CampaignId, m.MallId,
ROUND(#geo1.STDistance(geography::Point(m.MallLatitude, m.MallLongitude, 4326))/1000,1) AS Distance
FROM MallCampaign mc join
Mall m
ON m.MallId = mc.MallId
WHERE m.IsActive <> 0
ORDER BY mc.CampaignId, Distance;
EDIT:
Your original question didn't have a top in it, which I sort of expected. To handle this, you want to use row_number(). In this case, it is easiest to do two subqueries (or CTEs):
select CampaignId, MallId, Distance
from (select mc.*,
row_number() over (partition by CampaignId order by distance) as seqnum
from (SELECT mc.CampaignId, m.MallId,
ROUND(#geo1.STDistance(geography::Point(m.MallLatitude, m.MallLongitude, 4326))/1000,1) AS Distance
FROM MallCampaign mc join
Mall m
ON m.MallId = mc.MallId
WHERE m.IsActive <> 0
) mc
) mc
where seqnum = 1;