Task 2 in PostgreSQL

1 files changed, 21 insertions, 0 deletions

diff --git a/challenge-141/luca-ferrari/postgresql/ch-2.sql b/challenge-141/luca-ferrari/postgresql/ch-2.sql
new file mode 100644
index 0000000000..239d846b58
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+++ b/challenge-141/luca-ferrari/postgresql/ch-2.sql
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+CREATE OR REPLACE FUNCTION
+f_live_numbers( m int, n int )
+RETURNS SETOF int
+AS $CODE$
+WITH RECURSIVE
+numbers AS ( SELECT unnest( regexp_split_to_array( m::text, '' ) ) AS n )
+, combinations( i, v, c ) AS (
+SELECT 1, n, n
+FROM numbers
+UNION
+SELECT i + 1, n, c || num.n
+FROM combinations, numbers num
+WHERE length( c || num.n ) < length( m::text ) - 1
+AND num.n IN ( SELECT n FROM numbers WHERE n::int > i )
+)
+
+SELECT c::int FROM combinations
+WHERE c::int % n = 0;
+
+$CODE$
+LANGUAGE sql;