Group By Retrieve 4 Values - sql

Question

I have the following query
SELECT Cod ,
MIN(Id) AS id_Min,
-- retrieve value min in the middle as id_Min_Middle,
-- retrieve value max in the middle as id_Max_Middle,
MAX(Id) AS id_Max,
COUNT(*) AS Tot
FROM Table a ( NOLOCK )
GROUP BY Cod
HAVING COUNT(*)=4
How could I retrieve the values between min and max as I have done for min and max?
If I use (SUM(Id) - (MIN(Id)+MAX(Id)) I get the sum of middle min and max, but not the values I want.
EXAMPLES
Cod | Id
Stack 10
Stack 15
Stack 11
Stack 40
Overflow 1
Overflow 120
Overflow 15
Overflow 100
Required output
Cod | Min | Min_In_The_Middle | Max_In_The_Middle | Max
Stack 10 11 15 40
Overflow 1 15 100 120

Answer 1

Just only one [Table|[Clustered] Index]]Scan (demo here):
SELECT pvt.Cod,
pvt.[1] AS MinValue,
pvt.[2] AS MinInterValue,
pvt.[3] AS MaxInterValue,
pvt.[4] AS MaxValue
FROM
(
SELECT x.Cod, x.ID, x.RowNumAsc
FROM
(
SELECT *,
ROW_NUMBER() OVER(PARTITION BY t.Cod ORDER BY t.ID ASC) RowNumAsc,
ROW_NUMBER() OVER(PARTITION BY t.Cod ORDER BY t.ID DESC) RowNumDesc
FROM MyTable t
) x
WHERE x.RowNumAsc = 1 AND x.RowNumDesc = 4
OR x.RowNumAsc = 2 AND x.RowNumDesc = 3
OR x.RowNumAsc = 3 AND x.RowNumDesc = 2
OR x.RowNumAsc = 4 AND x.RowNumDesc = 1
) y
PIVOT ( MAX(y.ID) FOR y.RowNumAsc IN ([1], [2], [3], [4]) ) pvt;

Answer 2

Try using this, best of luck
WITH temp AS
(SELECT cod, MIN (ID) min_id, MAX (ID) max_id
FROM tab
GROUP BY cod
HAVING COUNT (ID) = 4)
SELECT code, temp.min_id,
(SELECT MIN (ID)
FROM tab
WHERE cod = temp.cod AND ID NOT IN (temp.min_id)
GROUP BY cod) min_mid_id,
(SELECT MAX (ID)
FROM tab
WHERE cod = temp.cod AND ID NOT IN (temp.max_id)
GROUP BY cod) max_min_id, temp.max_id
FROM temp;

Answer 3

I'm not sure what it means for your question to be tagged plsql and sql-server. But I'll assume you're working with a database system that supports CTEs and window functions.
To generalize what you're been trying to do, first assign row numbers to the rows, then use whatever technique you want to achieve the pivot:
;WITH OrderedValues as (
SELECT Cod,Id,ROW_NUMBER() OVER (PARTITION BY Cod ORDER BY Id) as rn
COUNT(*) OVER (PARTITION BY Cod) as Cnt
FROM Table (NOLOCK)
), With4Values as (
SELECT * from OrderedValues where Cnt=4
)
SELECT Cod,
--However you want to do the pivot. Here I'll use MAX/CASE
MAX(CASE WHEN rn=1 THEN Id END) as Value1,
MAX(CASE WHEN rn=2 THEN Id END) as Value2,
MAX(CASE WHEN rn=3 THEN Id END) as Value3,
MAX(CASE WHEN rn=4 THEN Id END) as Value4
FROM
With4Values
GROUP BY
Cod
You can hopefully see that this is more easily extended to more columns than answering your overly specific questions about 3 rows, or 4 rows. But if you need to deal with an arbitrary number of columns, you'll have to switch to dynamic SQL.

Answer 4

I understand you want to exclude the extreme values and find min and max for the rest.
This is what I think of, but I had no chance to run and test it...
WITH Extremes AS ( SELECT Cod, MAX(ID) AS Id_Max, MIN(ID) AS Id_Min
FROM [Table] a GROUP BY Cod)
SELECT
e.Cod,
e.Id_Min,
MIN(a.Id) AS id_Min_Middle,
MAX(a.Id) AS id_Max_Middle,
e.Id_Max
FROM Extremes e
LEFT JOIN [Table] a ON a.Cod = e.Cod AND a.Id > e.Id_Min AND a.Id < e.Id_Max
GROUP BY e.Cod