user: Question: How many deciles have an Authority of state and a Name of chertsey school?
Columns: ['Name', 'Years', 'Gender', 'Area', 'Authority', 'Decile', 'Roll']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'real']
Sample row: ['Allenton School', '1–6', 'Coed', 'Ashburton', 'State', 8.0, 343.0]
SQL:

assistant: SELECT COUNT("Decile") FROM "Table" WHERE "Authority" = 'state' AND "Name" = 'chertsey school';