user: Question: How many high rebounds were there on April 7?
Columns: ['Game', 'Date', 'Team', 'Score', 'High points', 'High rebounds', 'High assists', 'Location Attendance', 'Record']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [76.0, 'April 3', 'New Orleans', 'W 115–87 (OT)', 'Chris Douglas-Roberts (17)', 'Kris Humphries (12)', 'Terrence Williams (14)', 'Izod Center', '11-65']
SQL:

assistant: SELECT COUNT("High rebounds") FROM "Table" WHERE "Date" = 'April 7';