I tried these two queries and they are perfectly working fine:
SELECT FORMAT((SELECT COUNT(*) FROM xy), 2, 'de_DE');
SELECT FORMAT((SELECT count(*) FROM xy a WHERE a.typ = 'IHK' AND a.datum >=2014), 2, 'de_DE') AS anzahl;
the second query is from the error that you are getting, try this once, it should work. I tested it.
What is the version of MySQL that you are using? try this also:
SELECT FORMAT((SELECT COUNT(*) FROM xy), 2);
SELECT FORMAT((SELECT count(*) FROM xy a WHERE a.typ = 'IHK' AND a.datum >=2014), 2) AS anzahl;