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+--
+-- Perl Weekly Challenge 247
+-- Task 2
+--
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-247/>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc247;
+
+CREATE OR REPLACE FUNCTION
+pwc247.task2_plpgsql( string text )
+RETURNS TABLE( needle text, repetitions int )
+AS $CODE$
+
+DECLARE
+	needle text;
+BEGIN
+	CREATE TEMPORARY TABLE IF NOT EXISTS repetitions( needle text, repetition int );
+	TRUNCATE repetitions;
+
+	FOR i IN 1 .. length( string ) LOOP
+	    needle := substr( string, i, 2 );
+
+	    INSERT INTO repetitions
+	    SELECT needle, ( SELECT count(*) FROM  regexp_matches( string, needle, 'g' )f );
+
+	END LOOP;
+
+	RETURN QUERY
+	SELECT *
+	FROM repetitions
+	ORDER BY repetition DESC
+	LIMIT 1;
+
+END
+$CODE$
+LANGUAGE plpgsql;