Grouping like records - sql

Question

We have a set of data where there are 2 records for each CODE. An example of the data is this:
TICKER CODE SCORE PRICE PCF
---------------------------------------
ABC 23 A 100 20
DEF 23 B 200 30
XXX 52 C 300 40
YYY 52 D 400 50
GHI 86 E 500 60
JKL 86 F 600 70
MNO 27 G 700 80
PQR 27 H 800 90
So, what we need to do is create a query which will return the columns of the like records by CODE into 1 record like this:
CODE,TICKER_1,SCORE_1,PRICE_1,PCF_1,TICKER_2,SCORE_2,PRICE_2,PCF_2
23,ABC,A,100,20,DEF,B,200,30
52,XXX,C,300,40,YYY,D,400,40
86,GHI,E,500,60,JKL,F,600,70
27,MNO,G,700,80,PQR,H,800,90
So, that they are combined by like CODE values.

Answer 1

You may try the following which assigns uses ROW_NUMBER to assign a row number for each code entry before using MAX with a case expression to filter for each entry.
Eg.
SELECT
CODE,
MAX(CASE WHEN rn=1 THEN TICKER END) AS TICKER_1,
MAX(CASE WHEN rn=1 THEN SCORE END) AS SCORE_1,
MAX(CASE WHEN rn=1 THEN PRICE END) AS PRICE_1,
MAX(CASE WHEN rn=1 THEN PCF END) AS PCF_1,
MAX(CASE WHEN rn=2 THEN TICKER END) AS TICKER_2,
MAX(CASE WHEN rn=2 THEN SCORE END) AS SCORE_2,
MAX(CASE WHEN rn=2 THEN PRICE END) AS PRICE_2,
MAX(CASE WHEN rn=2 THEN PCF END) AS PCF_2
FROM (
SELECT
m.*,
ROW_NUMBER() OVER (PARTITION BY CODE ORDER BY TICKER) as rn
FROM mytable m
) m1
GROUP BY
CODE
Outputs:
CODE
TICKER_1
SCORE_1
PRICE_1
PCF_1
TICKER_2
SCORE_2
PRICE_2
PCF_2
23
ABC
A
100
20
DEF
B
200
30
27
MNO
G
700
80
PQR
H
800
90
52
XXX
C
300
40
YYY
D
400
50
86
GHI
E
500
60
JKL
F
600
70
For debugging purposes, the output of the subquery
SELECT
m.*,
ROW_NUMBER() OVER (PARTITION BY CODE ORDER BY TICKER) as rn
FROM mytable m
looks like this:
TICKER
CODE
SCORE
PRICE
PCF
RN
ABC
23
A
100
20
1
DEF
23
B
200
30
2
MNO
27
G
700
80
1
PQR
27
H
800
90
2
XXX
52
C
300
40
1
YYY
52
D
400
50
2
GHI
86
E
500
60
1
JKL
86
F
600
70
2
View working demo on db fiddle
Notable alternatives
Instead of CASE WHEN rn=1 THEN TICKER END you could also use the DECODE function available in oracle as DECODE(rn,1,TICKER)
You may also use a pivot as shown below (NB. Column names are not as in the expected result)
WITH cte as (
SELECT
m.*,
ROW_NUMBER() OVER (PARTITION BY CODE ORDER BY TICKER) as rn
FROM mytable m
)
SELECT * FROM cte
PIVOT (
MAX(TICKER) as "TICKER",
MAX(SCORE) as "SCORE",
MAX(PRICE) as "PRICE",
MAX(PCF) as "PCF"
FOR rn IN (1,2)
)
Outputs:
CODE
1_TICKER
1_SCORE
1_PRICE
1_PCF
2_TICKER
2_SCORE
2_PRICE
2_PCF
23
ABC
A
100
20
DEF
B
200
30
27
MNO
G
700
80
PQR
H
800
90
52
XXX
C
300
40
YYY
D
400
50
86
GHI
E
500
60
JKL
F
600
70
View working demo on db fiddle here