user: Question: Name the total number of ERP W when the call sign is w217bf
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text']
Sample row: ['W211BF', 90.1, 'Big Stone Gap, Virginia', 8.0, 'FCC']
SQL:

assistant: SELECT SUM("ERP W") FROM "Table" WHERE "Call sign" = 'w217bf';