user: Question: What are all approximate sales for the author Laura Ingalls Wilder?
Columns: ['Book series', 'Author', 'Original language', 'No. of installments', 'First published', 'Approximate sales']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Nijntje ( Miffy )', 'Dick Bruna', 'Dutch', '119', '1955 — present', '85 million']
SQL:

assistant: SELECT "Approximate sales" FROM "Table" WHERE "Author" = 'Laura Ingalls Wilder';