user: Question: how many teams had an appointment date of 11 April 2011
Columns: ['Team', 'Outgoing manager', 'Manner of departure', 'Date of vacancy', 'Replaced by', 'Date of appointment', 'Position in table']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Valladolid', 'Javier Clemente', 'End of contract', '31 May 2010', 'Antonio Gómez', '23 June 2010', '18th (in La Liga )']
SQL:

assistant: SELECT COUNT("Team") FROM "Table" WHERE "Date of appointment" = '11 April 2011';