user: Question: How many couples won the Mixed Doubles in 1997?
Columns: ['Year', 'Mens singles', 'Womens singles', 'Mens doubles', 'Womens doubles', 'Mixed doubles']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1977.0, 'Victor Yusim', 'Chaya Grunstein', 'Victor Yusim Michael Schneidman', 'Vivian Meirowitz Carol Silman', 'Michael Schneidman Dianne Levi']
SQL:

assistant: SELECT COUNT("Mixed doubles") FROM "Table" WHERE "Year" = 1997.0;