user: Question: How many years Joined have a Size smaller than 417, and an IHSaa Class of a, and a School of jac-cen-del?
Columns: ['School', 'Location', 'Mascot', 'Size', 'IHSAA Class', 'County', 'Year Joined', 'Previous Conference']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['Jac-Cen-Del', 'Osgood', 'Eagles', 296.0, 'A', '69 Ripley', 1960.0, 'none (new school)']
SQL:

assistant: SELECT COUNT("Year Joined") FROM "Table" WHERE "Size" < 417.0 AND "IHSAA Class" = 'a' AND "School" = 'jac-cen-del';