How can I write a SQL query to map rows into columns? - sql

Question

Consider the following query from a database,
SELECT propertyname,propertyvalue,value,
FROM db
which returns
| propertyname | propertyvalue | value |
+--------------------+----------------+----------+
| AnimalNumber | 1 | 1.3 |
| Group | 1 | 1.3 |
| TimePoint | 24 days | 1.3 |
| Treatment method | vehicle | 1.3 |
| Treatment Conc | 0 | 1.3 |
| AnimalNumber | 2 | 0.5 |
| Group | 3 | 0.5 |
| TimePoint | 7 days | 0.5 |
| Treatment method | vehicle | 0.5 |
| Treatment Conc | 0 | 0.5 |
We can see it's the case that multiple rows map to the same 'value' datapoint. Really, it should be the case that each of those 5 properties (animal number, group, time point, treatment method, treatment conc) should be columns and the first 5 data points should be condensed into a single row with a value=1.3. In other words, it should be something like
| AnimalNumber | Group | TimePoint | Treatment method | Treatment Conc | value
+--------------+-------+-----------+------------------+-----------------+------+
| 1 | 1 | 24 days | vehicle | 0 | 1.3 |
| 2 | 3 | 7 days | vehicle | 0 | 0.5 |
Also note that it is not necessarily the case that there is a 1-1 mapping to value, multiple combinations of animal number, group, timepoint, treatment method, and treatment conc can map to to the same value. So grouping by value I do not believe is the proper approach. Also note that all data provided here is, of course, fabricated and not real.

Answer 1

You can use PIVOT:
SELECT *
FROM table_name
PIVOT(
MAX(propertyvalue)
FOR propertyname IN (
'AnimalNumber' AS animalnumber,
'Group' AS "GROUP",
'TimePoint' AS TimePoint,
'Treatment method' AS TreatementMethod,
'Treatment Conc' AS TreatmentConc
)
)
Which, for your sample data:
CREATE TABLE table_name ( propertyname, propertyvalue, value ) AS
SELECT 'AnimalNumber', '1', 1.3 FROM DUAL UNION ALL
SELECT 'Group', '1', 1.3 FROM DUAL UNION ALL
SELECT 'TimePoint', '24 days', 1.3 FROM DUAL UNION ALL
SELECT 'Treatment method', 'vehicle', 1.3 FROM DUAL UNION ALL
SELECT 'Treatment Conc', '0', 1.3 FROM DUAL UNION ALL
SELECT 'AnimalNumber', '2', 0.5 FROM DUAL UNION ALL
SELECT 'Group', '3', 0.5 FROM DUAL UNION ALL
SELECT 'TimePoint', '7 days', 0.5 FROM DUAL UNION ALL
SELECT 'Treatment method', 'vehicle', 0.5 FROM DUAL UNION ALL
SELECT 'Treatment Conc', '0', 0.5 FROM DUAL;
Outputs:
VALUE
ANIMALNUMBER
GROUP
TIMEPOINT
TREATEMENTMETHOD
TREATMENTCONC
0.5
2
3
7 days
vehicle
0
1.3
1
1
24 days
vehicle
0
db<>fiddle here

Answer 2

one way is to group by value :
select max(propertyvalue) filter(where propertyname='AnimalNumber') AnimalNumber
, max(propertyvalue) filter(where propertyname='TimePoint') TimePoint
, max(propertyvalue) filter(where propertyname='Treatment method') "Treatment method"
, max(propertyvalue) filter(where propertyname='Treatment Conc') "Treatment Conc"
, max(propertyvalue) filter(where propertyname='Group') "Group"
from tablename
group by value