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September 2017 Update

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This commit is contained in:
Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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74
Task/Forward-difference/SQL/forward-difference.sql
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@ -1,37 +1,37 @@
create table list (n integer, v real);
insert into list values (0, 90);
insert into list values (1, 47);
insert into list values (2, 58);
insert into list values (3, 29);
insert into list values (4, 22);
insert into list values (5, 32);
insert into list values (6, 55);
insert into list values (7, 5);
insert into list values (8, 55);
insert into list values (9, 73);
create view diff1 as select list.n, (select next.v from list as next where next.n = list.n + 1) - list.v as v from list;
create view diff2 as select list.n, (select next.v from diff1 as next where next.n = list.n + 1) - list.v as v from diff1 as list;
select * from diff1;
0|-43.0
1|11.0
2|-29.0
3|-7.0
4|10.0
5|23.0
6|-50.0
7|50.0
8|18.0
9|
select * from diff2;
0|54.0
1|-40.0
2|22.0
3|17.0
4|13.0
5|-73.0
6|100.0
7|-32.0
8|
9|
WITH RECURSIVE
T0 (N, ITEM, LIST, NEW_LIST) AS
(
SELECT 1,
NULL,
'90,47,58,29,22,32,55,5,55,73' || ',',
NULL
UNION ALL
SELECT CASE
WHEN SUBSTR(LIST, INSTR(LIST, ',') + 1, LENGTH(LIST)) = ''
THEN N + 1
ELSE N
END,
CASE
WHEN SUBSTR(LIST, INSTR(LIST, ',') + 1, LENGTH(LIST)) <> ''
THEN SUBSTR(LIST, 1, INSTR(LIST, ',') - 1)
ELSE NULL
END,
CASE
WHEN SUBSTR(LIST, INSTR(LIST, ',') + 1, LENGTH(LIST)) = ''
THEN IFNULL(NEW_LIST || (SUBSTR(LIST, 1, INSTR(LIST, ',') - 1) - ITEM) || ',', '')
ELSE SUBSTR(LIST, INSTR(LIST, ',') + 1, LENGTH(LIST))
END,
CASE
WHEN SUBSTR(LIST, INSTR(LIST, ',') + 1, LENGTH(LIST)) <> ''
THEN IFNULL(NEW_LIST, '') || IFNULL((SUBSTR(LIST, 1, INSTR(LIST, ',') - 1) - ITEM) || ',', '')
ELSE NULL
END
FROM T0
WHERE INSTR(LIST, ',') > 0
)
SELECT N,
TRIM(LIST, ',') LIST
FROM T0
WHERE NEW_LIST IS NULL
AND LIST <> ''
ORDER BY N;