Building totals based on condition in another row - tsql

Question

Really struggling to understand the best way of doing this...
I have a table of data
**StudentID AssessmentCode ResultGroup Result**
46933 12ENG IBLevel HL
46933 12ENG Mark 6
46933 12ECO IBLevel HL
46933 12ECO Mark 5
46933 12GEO IBLevel SL
46933 12GEO Mark 6
46933 12LAN IBLevel HL
46933 12LAN Mark 4
46933 12PED IBLevel SL
46933 12PED Mark 5
46933 12SCI IBLevel SL
46933 12SCI Mark 3
67767 12FRE IBLevel HL
67767 12FRE Mark 4
67767 12MAT IBLevel SL
67767 12MAT Mark 5
and so on...
Unfortunately the result column holds 2 different bits of info. The level a student does (HL = High Level; SL = Standard Level) and then the result for that subject at that level. Note that for each student, 2 rows are generated per subject a student does, one row has the IBLevel and the next row has the result for that level.
How can I rearrange the data to get something like
StudentID HLResult SLResult TotalResult CountofHL CountofSL
46933 15 14 29 3 3
67767 13 10 23 4 2
So each student has one row of data with totals for HL, SL, both together and then a count of the number of HL and SL subjects. As I said, really not sure of the best way of going about this. In the end, I would also like to extend this to get some columns which, based on the results give some warning messages eg the TotalResult has to be great than 24 so I would love a column that simply returns whether this has been achieved or not...
StudentID HLResult SLResult TotalResult CountofHL CountofSL MoreThan24
46933 15 14 29 3 3 True
67767 13 10 23 4 2 False
Any help would be greatly appreciated...

Answer 1

Your table seems to have some serious normalization issues. You have to perform an INNER JOIN on AssessmentCode first:
SELECT t1.StudentID, t1.AssessmentCode,
t1.Result AS Level, CAST(t2.Result AS INT) AS Mark
FROM (
SELECT StudentID, AssessmentCode, Result
FROM mytable
WHERE ResultGroup = 'IBLevel' ) AS t1
INNER JOIN (
SELECT StudentID, AssessmentCode, Result
FROM mytable
WHERE ResultGroup = 'Mark' ) AS t2
ON t1.StudentID = t2.StudentID AND t1.AssessmentCode = t2.AssessmentCode
to get one row per AssessmentCode.
Output:
StudentID AssessmentCode Level Mark
-----------------------------------------
46933 12ENG HL 6
46933 12ECO HL 5
46933 12GEO SL 6
46933 12LAN HL 4
46933 12PED SL 5
46933 12SCI SL 3
67767 12FRE HL 4
67767 12MAT SL 5
You can now wrap the above query in a CTE and perform conditional aggregation to get required result:
;WITH CTE AS (
... above query here
)
SELECT StudentID,
SUM(CASE WHEN Level = 'HL' THEN Mark ELSE 0 END) AS HLResult,
SUM(CASE WHEN Level = 'SL' THEN Mark ELSE 0 END) AS SLResult,
SUM(Mark) AS TotalResult,
COUNT(CASE WHEN Level = 'HL' THEN 1 END) AS CountofHL,
COUNT(CASE WHEN Level = 'SL' THEN 1 END) AS CountofSL,
CASE WHEN SUM(Mark) > 24 THEN 'True'
ELSE 'False'
END AS MoreThan24
FROM CTE
GROUP BY StudentID
Output:
StudentID HLResult SLResult TotalResult CountofHL CountofSL MoreThan24
46933 15 14 29 3 3 True
67767 4 5 9 1 1 False
Demo here

Answer 2

My Version of Your Table
DECLARE #yourTable TABLE
(
StudentID INT,
AssessmentCode CHAR(5),
ResultGroup VARCHAR(10),
Result VARCHAR(5)
)
INSERT INTO #yourTable
VALUES (46933,'12ENG','IBLevel','HL'),
(46933,'12ENG','Mark','6'),
(46933,'12ECO','IBLevel','HL'),
(46933,'12ECO','Mark','5'),
(46933,'12GEO','IBLevel','SL'),
(46933,'12GEO','Mark','6'),
(46933,'12LAN','IBLevel','HL'),
(46933,'12LAN','Mark','4'),
(46933,'12PED','IBLevel','SL'),
(46933,'12PED','Mark','5'),
(46933,'12SCI','IBLevel','SL'),
(46933,'12SCI','Mark','3'),
(67767,'12FRE','IBLevel','HL'),
(67767,'12FRE','Mark','4'),
(67767,'12MAT','IBLevel','SL'),
(67767,'12MAT','Mark','5');
Actual Query
WITH CTE_ResultValue
AS
(
SELECT StudentID,
AssessmentCode,
ResultGroup,
CAST(Result AS INT) AS ResultValue
FROM #yourTable
WHERE ISNUMERIC(Result) = 1
),
CTE_IBLevel
AS
(
SELECT StudentID,
AssessmentCode,
Result AS IBLevel
FROM #yourTable
WHERE ISNUMERIC(Result) = 0
),
CTE_Normalized
AS
(
SELECT A.StudentID,
A.AssessmentCode,
A.ResultGroup,
A.ResultValue,
B.IBLevel
FROM CTE_ResultValue AS A
INNER JOIN CTE_IBLevel AS B
ON A.StudentID = B.StudentID
AND A.AssessmentCode = B.AssessmentCode
)
SELECT [StudentID],
[HLResult] = SUM(CASE WHEN IBLevel = 'HL' THEN ResultValue END),
[SLResult] = SUM(CASE WHEN IBLevel = 'SL' THEN ResultValue END),
[TotalResult] = SUM(ResultValue),
[CountOfHL] = SUM(CASE WHEN IBLevel = 'HL' THEN 1 END),
[CountOfSL] = SUM(CASE WHEN IBLevel = 'SL' THEN 1 END)
FROM CTE_Normalized
GROUP BY StudentID
Normalization
Your table is in serious need of normalization. If you can change it, bare minimal change would look like this:
CREATE TABLE dbo.NormalizedTable
(
StudentID INT,
AssessmentCode CHAR(5),
ResultGroup VARCHAR(25),
ResultValue SMALLINT, --smallint range should be plenty. It can store values from -32,768 to 32,767
IBLevel CHAR(2)
)
INSERT INTO dbo.NormalizedTable
SELECT *
FROM CTE_Normalized
If you can't change the way your data is structured, I'd recommend creating a view from my CTE_normalized
CREATE VIEW vw_normalizedTable
AS
WITH CTE_ResultValue
AS
(
SELECT StudentID,
AssessmentCode,
ResultGroup,
CAST(Result AS INT) AS ResultValue
FROM #yourTable
WHERE ISNUMERIC(Result) = 1
),
CTE_IBLevel
AS
(
SELECT StudentID,
AssessmentCode,
Result AS IBLevel
FROM #yourTable
WHERE ISNUMERIC(Result) = 0
),
SELECT A.StudentID,
A.AssessmentCode,
A.ResultGroup,
A.ResultValue,
B.IBLevel
FROM CTE_ResultValue AS A
INNER JOIN CTE_IBLevel AS B
ON A.StudentID = B.StudentID
AND A.AssessmentCode = B.AssessmentCode
GO

Answer 3

Version1:
SELECT t1.StudentID,
SUM(CASE WHEN t1.Result = 'HL' THEN t2.Result ELSE 0 END) HLResult,
SUM(CASE WHEN t1.Result = 'SL' THEN t2.Result ELSE 0 END) SLResult,
SUM(CAST(t2.Result AS INT)) TotalResult,
SUM(CASE WHEN t1.Result = 'HL' THEN 1 ELSE 0 END) CountofHL,
SUM(CASE WHEN t1.Result = 'SL' THEN 1 ELSE 0 END) CountofSL,
CASE WHEN SUM(CAST(t2.Result AS INT)) > 24 THEN 'True' ELSE 'False' END MoreThan24
FROM #t t1
JOIN #t t2 ON t1.StudentID = t2.StudentID AND
t1.AssessmentCode = t2.AssessmentCode AND
t1.ResultGroup = 'IBLevel' AND
t2.ResultGroup = 'Mark'
GROUP BY t1.StudentID
Version2:
WITH cte1 AS(
SELECT *, ROW_NUMBER() OVER(PARTITION BY StudentID, AssessmentCode
ORDER BY CASE WHEN ResultGroup = 'IBLevel' THEN 1 ELSE 2 END) AS rn FROM #t),
cte2 AS(SELECT StudentID,
AssessmentCode,
SUM(CASE WHEN Result = 'HL' THEN 1 ELSE 0 END) HL,
SUM(CASE WHEN Result = 'SL' THEN 1 ELSE 0 END) SL,
MAX(CASE WHEN rn = 2 THEN Result END) R
FROM cte1
GROUP BY StudentID, AssessmentCode)
SELECT StudentID,
SUM(hl*R) HLResult,
SUM(sl*R) SLResult,
SUM((hl + sl)*r) TotalResult,
SUM(hl) CountofHL,
SUM(sl) CountofSL,
CASE WHEN SUM((hl + sl)*r) > 24 THEN 'True' ELSE 'False' END MoreThan24
FROM cte2
GROUP BY StudentID
Output:
StudentID HLResult SLResult TotalResult CountofHL CountofSL MoreThan24
46933 15 14 29 3 3 True
67767 4 5 9 1 1 False
Just replace #t with your table.