Database: european_football_2
Question: How many matches were held in the Belgium Jupiler League in April, 2009?
SQL: SELECT COUNT(t2.id) FROM League AS t1 INNER JOIN Match AS t2 ON t1.id = t2.league_id WHERE t1.name = 'Belgium Jupiler League' AND SUBSTR(t2.`date`, 1, 7) = '2009-04'