Remove duplicate address_id from sql data set - sql

Question

I need to get only distinct address_id in result no duplication. Here is my query.
SELECT DISTINCT address.address_id, address.address1, address.streetcity, state.stateabbrev, rtrim(ltrim(case when address.streetzipcode is not null and address.streetzipcode != 'NULL' then address.streetzipcode else '' end))+case when len(address.streetzipplus4)>0 then '-'+rtrim(ltrim(address.streetzipplus4)) else '' end as streetzipcode, address.homephone,
dbo.f_addressstudent (student.address_id) as Students,
dbo.f_addresspeople (student.address_id) as Adults,
case
when #classif_id IS NULL then 0
else
student.classif_id
end classif,
classifctn
FROM district WITH(NOLOCK)
JOIN dbo.building ON building.district_id = district.district_id
JOIN dbo.studbldg_bridge WITH(NOLOCK) ON studbldg_bridge.bldg_id=building.bldg_id
JOIN dbo.student WITH(NOLOCK) ON student.student_id = studbldg_bridge.student_id
JOIN classif with(nolock) on student.classif_id = classif.classif_id
LEFT JOIN dbo.address WITH(NOLOCK) ON student.address_id = address.address_id
LEFT JOIN dbo.state WITH(NOLOCK) ON address.streetstate_id = state.state_id
LEFT JOIN dbo.state AS mailstate WITH(NOLOCK) ON address.state_id = mailstate.state_id
WHERE district.district_id = (SELECT district_id FROM dbo.building WITH(NOLOCK) WHERE bldg_id = #bldg_id)
ORDER BY classif,Adults, Students
Here is result of query
Query result with error in data
I have tried to group by and use aggregate function with address_id but I also have non-aggregate columns so it didn't worked for me.
After that I also tried using OVER(partition by address.address_id) but it also didn't worked.
Any help will be appreciated in advance.
Thank you
**UPDATE on Business logic/Requirements **
I need to get unique addresses for parents of students. As parent can have two or more children living in same address, it causes duplication. I need to get only one child per parent in other words.

Answer 1

From your image of the results it looks like the classifctn column has more than 1 value so it is repeating your row by that. In order to get 1 distinct address_id and rest of the columns either remove it from your query or you can set a precedence that will only return 1 record per address_id
further please tag only the RDBMs you ware actually using. MySQL for example doesn't have window functions yet you tagged it yet referenced using OVER(partition.... which would not be possible in mysql
;WITH cte (
SELECT DISTINCT address.address_id, address.address1, address.streetcity, state.stateabbrev, rtrim(ltrim(case when address.streetzipcode is not null and address.streetzipcode != 'NULL' then address.streetzipcode else '' end))+case when len(address.streetzipplus4)>0 then '-'+rtrim(ltrim(address.streetzipplus4)) else '' end as streetzipcode, address.homephone,
dbo.f_addressstudent (student.address_id) as Students,
dbo.f_addresspeople (student.address_id) as Adults,
case
when #classif_id IS NULL then 0
else
student.classif_id
end classif,
classifctn,
ROW_NUMBER() OVER (PARTITION BY address.address_id ORDER BY HOW WILL YOU CHOOSE?) AS RowNum
FROM district WITH(NOLOCK)
JOIN dbo.building ON building.district_id = district.district_id
JOIN dbo.studbldg_bridge WITH(NOLOCK) ON studbldg_bridge.bldg_id=building.bldg_id
JOIN dbo.student WITH(NOLOCK) ON student.student_id = studbldg_bridge.student_id
JOIN classif with(nolock) on student.classif_id = classif.classif_id
LEFT JOIN dbo.address WITH(NOLOCK) ON student.address_id = address.address_id
LEFT JOIN dbo.state WITH(NOLOCK) ON address.streetstate_id = state.state_id
LEFT JOIN dbo.state AS mailstate WITH(NOLOCK) ON address.state_id = mailstate.state_id
WHERE district.district_id = (SELECT district_id FROM dbo.building WITH(NOLOCK) WHERE bldg_id = #bldg_id)
)
SELECT *
FROM
cte
WHERE
RowNum = 1
ORDER BY
classif
,Adults
,Students
Alternatively you could nest your select query. note though this solution is somewhat useless as it will only return 1 grade/classifctn when more than 1 exists in a household if you really don't care about the column then you should just remove it from your query.
Actually both your classifctn and classif columns will cause you multiple rows when more than 1 student is at the same address. here is a way to concatenate those values to a single row. You should spend some more time on your business case and defining it for us. But here is one example for you:
SELECT DISTINCT
address.address_id
,address.address1
,address.streetcity
,state.stateabbrev
,LTRIM(RTRIM(ISNULL(NULLIF(address.streetzipcode,'NULL'),'')))
+ CASE WHEN LEN(address.streetzipplus4) > 0 THEN '-' ELSE '' END
+ LTRIM(RTRIM(ISNULL(address.streetzipplus4,''))) AS streetzipcode
,address.homephone
,dbo.f_addressstudent (student.address_id) as Students
,dbo.f_addresspeople (student.address_id) as Adults
, case
when #classif_id IS NULL then 0
else student.classif_id
end classif
,STUFF(
(SELECT ',' + CAST(classif_id AS VARCHAR(100))
FROM
classif c
WHERE c.classif = student.classif
FOR XML PATH(''))
,1,1,'') AS classifs
,STUFF(
(SELECT ',' + CAST(classifctn AS VARCHAR(100))
FROM
classif c
WHERE c.classif = student.classif
FOR XML PATH(''))
,1,1,'') AS classifctns
FROM
district WITH(NOLOCK)
INNER JOIN dbo.building
ON building.district_id = district.district_id
AND building.bldg_id = #bldg_id
INNER JOIN dbo.student WITH(NOLOCK)
ON student.student_id = studbldg_bridge.student_id
INNER JOIN dbo.address WITH(NOLOCK)
ON student.address_id = address.address_id
LEFT JOIN dbo.state WITH(NOLOCK)
ON address.streetstate_id = state.state_id
Note I when ahead and changed the zip code logic to show you some use of ISNULL() and NULLIF() that are helpful in cases like that. I also removed 3 tables because 2 are not used and the third ends up being used in a subselect to concatenate the values. Also address table was changed to an INNER JOIN because if an address doesn't exist all of the other information becomes blank/useless....
INNER JOIN dbo.studbldg_bridge WITH(NOLOCK) ON studbldg_bridge.bldg_id=building.bldg_id
LEFT JOIN dbo.state AS mailstate WITH(NOLOCK) ON address.state_id = mailstate.state_id
INNER JOIN classif with(nolock) on student.classif_id = classif.classif_id