user: Question: How many production codes are there for episode number 45?
Columns: ['No.', '#', 'Title', 'Director', 'Writer(s)', 'Original air date', 'Prod. code', 'U.S. viewers (million)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [44.0, 1.0, '"Those Lazy-Hazy-Crazy Days"', 'Amy Sherman-Palladino', 'Amy Sherman-Palladino', 'September24,2002', 175001.0, '5.7']
SQL:

assistant: SELECT COUNT("Prod. code") FROM "Table" WHERE "No." = 45.0;