Unified records for database query with Sql - sql

Question

Basic need is if a record has an Attribute of "Urgent", then the attributevalue should be displayed in the Urgent column. If the record has an attribute value of "closed", then the attributevalue must be displayed in the "Closed" column.
I have a query below. My problem is that among the results I am getting back, there are two records with the same RequesterID (one with a valid value in "Urgent" column and one with a value in "Closed" colum)
My problem is that I need these two particular records to be displayed as one record.
Any ideas?
SELECT DISTINCT
r.RequesterID,
sr.ModifiedDate,
p.FirstName + ' ' + p.LastName AS RequesterName,
CASE
WHEN sa.Attribute = 'Urgent' THEN sa.AttributeValue
ELSE NULL
END AS Urgent,
CASE
WHEN sa.Attribute = 'Closed' THEN sa.AttributeValue
ELSE NULL
END AS Closed
FROM
Requester AS r
INNER JOIN SubRequester AS sr
ON r.RequesterID = sr.RequesterID
INNER JOIN SubRequesterAttribute AS sa
ON sr.SubRequesterID = sa.SubRequesterID
CROSS JOIN Personnel AS p
WHERE
(r.UserID = p.ContractorID
OR r.UserID = p.EmployeeID)
AND
(sa.Attribute IN ('Urgent', 'Closed'))
GROUP BY r.RequesterID, sr.ModifiedDate, p.FirstName, p.LastName,
sa.Attribute, sa.AttributeValue

Answer 1

You will need to join to your sub requester attribute table to the query twice. One with the attribute of Urgent and one with the attribute of Close.
You will need to LEFT join to these for the instances where they may be null and then reference each of the tables in your SELECT to show the relevent attribute.
I also wouldn't reccomend the cross join. You should perform your "OR" join on the personnel table in the FROM clause rather than doing a cross join and filtering in the WHERE clause.
EDIT: Sorry, my first response was a bit rushed. Have now had a chance to look further. Due to the sub requester and the sub requester attribute both being duplicates you need to split them both up into a subquery. Also, your modified date could be different for both values. So i've doubled that up. This is completely untested, and by no means the "optimum" solution. It's quite tricky to write the query without the actual database to check against. Hopefully it will explain what I meant though.
SELECT
r.RequesterID,
p.FirstName + ' ' + p.LastName AS RequesterName,
sra1.ModifiedDate as UrgentModifiedDate,
sra1.AttributeValue as Urgent,
sra2.ModifiedDate as ClosedModifiedDate,
sra2.AttributeValue as Closed
FROM
Personnel AS p
INNER JOIN
Requester AS r
ON
(
r.UserID = p.ContractorID
OR
r.UserID = p.EmployeeID
)
LEFT OUTER JOIN
(
SELECT
sr1.RequesterID,
sr1.ModifiedDate,
sa1.Attribute,
sa1.AttributeValue
FROM
SubRequester AS sr1
INNER JOIN
SubRequesterAttribute AS sa1
ON
sr1.SubRequesterID = sa1.SubRequesterID
AND
sa1.Attribute = 'Urgent'
) sra1
ON
sra1.RequesterID = r.RequesterID
LEFT OUTER JOIN
(
SELECT
sr2.RequesterID,
sr2.ModifiedDate,
sa2.Attribute,
sa2.AttributeValue
FROM
SubRequester AS sr2
INNER JOIN
SubRequesterAttribute AS sa2
ON
sr2.SubRequesterID = sa2.SubRequesterID
AND
sa2.Attribute = 'Closed'
) sra1
ON
sra2.RequesterID = r.RequesterID
SECOND EDIT: My last edit was that there were multiple SubRequesters as well as multiple Attribute, from your last comment you want to show all SubRequesters and the two relevent attributes? You can achieve this as follows.
SELECT
r.RequesterID,
p.FirstName + ' ' + p.LastName AS RequesterName,
sr.ModifiedDate,
sa1.AttributeValue as Urgent,
sa2.AttributeValue as Closed
FROM
Personnel AS p
INNER JOIN
Requester AS r
ON
(
r.UserID = p.ContractorID
OR
r.UserID = p.EmployeeID
)
INNER JOI N
SubRequester as sr
ON
sr.RequesterID = r.RequesterID
LEFT OUTER JOIN
SubRequesterAttribute AS sa1
ON
sa1.SubRequesterID = sr.SubRequesterID
AND
sa1.Attribute = 'Urgent'
LEFT OUTER JOIN
SubRequesterAttribute AS sa2
ON
sa2.SubRequesterID = sr.SubRequesterID
AND
sa2.Attribute = 'Closed'

Answer 2

Generally, if you have multiple rows and want to collapse them into one, GROUP BY is the basic tool to achieve that. It looks like you tried to go in that direction but didn't quite get there. What you want to do is group by the expressions that are duplicated between the rows, and apply group functions to the other expressions that will eliminate the NULL values. I used MIN in the example below but you could just as easily use MAX; the point is that since at most one of the rows will have a value for that expression, that value is both the minimum and the maximum.
SELECT
r.RequesterID,
sr.ModifiedDate,
p.FirstName + ' ' + p.LastName AS RequesterName,
MIN(
CASE
WHEN sa.Attribute = 'Urgent' THEN sa.AttributeValue
ELSE NULL
END
) AS Urgent,
MIN(
CASE
WHEN sa.Attribute = 'Closed' THEN sa.AttributeValue
ELSE NULL
END
) AS Closed
FROM
Requester AS r
INNER JOIN SubRequester AS sr
ON r.RequesterID = sr.RequesterID
INNER JOIN SubRequesterAttribute AS sa
ON sr.SubRequesterID = sa.SubRequesterID
CROSS JOIN Personnel AS p
WHERE
(r.UserID = p.ContractorID
OR r.UserID = p.EmployeeID)
AND
(sa.Attribute IN ('Urgent', 'Closed'))
GROUP BY r.RequesterID, sr.ModifiedDate, p.FirstName + ' ' + p.LastName