Task 1 done plpgsql

1 files changed, 22 insertions, 0 deletions

diff --git a/challenge-198/luca-ferrari/postgresql/ch-1.sql b/challenge-198/luca-ferrari/postgresql/ch-1.sql
new file mode 100644
index 0000000000..b5b1e7fdbb
--- /dev/null
+++ b/challenge-198/luca-ferrari/postgresql/ch-1.sql
@@ -0,0 +1,22 @@
+CREATE SCHEMA IF NOT EXISTS pwc198;
+
+CREATE OR REPLACE FUNCTION
+pwc198.task1_plpgsql( l int[] )
+RETURNS int
+AS $CODE$
+
+   with counting as (
+      select v, v - lag( v, 1, v ) over w as d
+      from unnest( l ) v
+      window w as (order by v asc )
+   )
+   , max_counting as (
+     select max( d ) from counting
+   )
+   select count(*)
+   from counting
+   where d = ( select * from max_counting );
+
+
+$CODE$
+LANGUAGE sql;