user: Question: How many times did Niels Christian Kaldau win the men's single and Pi Hongyan win the women's single in the same year?
Columns: ['Year', 'Mens singles', 'Womens singles', 'Mens doubles', 'Womens doubles', 'Mixed doubles']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1988.0, 'Kim Brodersen', 'Katrin Schmidt', 'Markus Keck Robert Neumann', 'Katrin Schmidt Nicole Baldewein', 'Markus Keck Katrin Schmidt']
SQL:

assistant: SELECT COUNT("Year") FROM "Table" WHERE "Mens singles" = 'Niels Christian Kaldau' AND "Womens singles" = 'Pi Hongyan';