Combining two tables with a PIVOT statement - SQL Oracle 11g - sql

Question

I have a table like this called DWH_DATA:
DATETIME FK_FEDERAL_STATE FK_ACCOMODATION ARRIVALS NIGHTS
--------------- -------------------- --------------- ---------- ----------
200010 W96-7 61 2433 16111
200011 W96-9 86 3718 30319
200012 W96-3 87 1100 8487
200101 W96-2 998 239 1038
Additional info Datetime = first four number = year + last two numbers = month
Then I have a table DWH_FEDERAL_STATES:
CODE(PK) NAME
---------- -------------------
W96-2 Country 2
W96-3 Country 3
W96-9 Country 9
W96-7 Country 7
Now I would like to get all nights for each federal state. Result should look like this:
Country 2 Country 3 Country 9 Country 7
200010 6979 16111
200011 ..
200012 ..
200101 ..
What I've already tried is a PIVOT Statement:
SELECT * FROM
(
SELECT
DATETIME,
NIGHTS,
dwh_data.fk_federal_state As federalState
FROM
dwh_data JOIN DWH_FEDERAL_STATES
ON dwh_data.fk_federal_state = dwh_federal_states.code
) t
PIVOT(
COUNT(federalState)
FOR federalState IN ('Country 2','Country 3','Country 9')
) ORDER BY 1;
The result I get with mine is:
DATETIME NIGHTS 'Country 2' 'Country 3' 'Country 9'
-------------------- ---------- ----------- ----------- -----------
197707 83648 0 0 0
197707 87301 0 0 0
197707 97350 0 0 0

Answer 1

You don't want to COUNT, you want to SUM the nights and use the name column:
SELECT datetime,
COALESCE(country_2, 0) AS country_2,
COALESCE(country_3, 0) AS country_3,
COALESCE(country_9, 0) AS country_9
FROM (
SELECT d.DATETIME,
nights,
f.name
FROM dwh_data d
JOIN DWH_FEDERAL_STATES f
ON d.fk_federal_state = f.code
)
PIVOT(
SUM(nights)
FOR name IN (
'Country 2' AS country_2,
'Country 3' AS country_3,
'Country 9' AS country_9
)
)
ORDER BY
datetime;
Which, for the sample data:
CREATE TABLE dwh_data (DATETIME, FK_FEDERAL_STATE, FK_ACCOMODATION, ARRIVALS, NIGHTS) AS
SELECT 200010, 'W96-7', 61, 2433, 16111 FROM DUAL UNION ALL
SELECT 200011, 'W96-9', 86, 3718, 30319 FROM DUAL UNION ALL
SELECT 200012, 'W96-3', 87, 1100, 8487 FROM DUAL UNION ALL
SELECT 200101, 'W96-2', 998, 239, 1038 FROM DUAL;
CREATE TABLE DWH_FEDERAL_STATES (CODE, NAME) AS
SELECT 'W96-2', 'Country 2' FROM DUAL UNION ALL
SELECT 'W96-3', 'Country 3' FROM DUAL UNION ALL
SELECT 'W96-9', 'Country 9' FROM DUAL UNION ALL
SELECT 'W96-7', 'Country 7' FROM DUAL;
Outputs:
DATETIME
COUNTRY_2
COUNTRY_3
COUNTRY_9
200010
0
0
0
200011
0
0
30319
200012
0
8487
0
200101
1038
0
0
db<>fiddle here