PatNr   EventDate   MTA
1   2003-09-01  3
4   2008-10-21  3
4   2008-04-23  3
4   2007-03-05  3
4   2007-10-31  3

SELECT Patienten . * , GROUP_CONCAT( IF( CerebrovaskulaereEreignisse.PatNr = Patienten.PatNr, CerebrovaskulaereEreignisse.MTA, NULL ) ) AS 'MTA'
FROM Patienten
JOIN CerebrovaskulaereEreignisse ON Patienten.PatNr = CerebrovaskulaereEreignisse.PatNr
GROUP BY Patienten.PatNr
LIMIT 0 , 30

PatNr   BirthDate   Begin           Status  Sex     MTA
1   1940-04-29  2001-09-10  1   2   [BLOB - 1B]
4   1948-01-24  2002-01-29  1   2   [BLOB - 7B]
6   1969-02-02  2001-02-13  1   1   [BLOB - 1B]
7   1940-06-06  2001-02-13  1   2   [BLOB - 1B]
11  1952-05-31  2001-07-09  1   1   [BLOB - 1B]
12  1961-08-11  2000-11-29  1   1   [BLOB - 3B]