Accepted solution using NOT EXISTS
\nSELECT  s.name\nFROM    salesperson s\nWHERE   NOT EXISTS (\n    SELECT  s.name\n    FROM    company c, orders o\n    WHERE   s.sales_id = o.sales_id \n      
```\nSELECT  s.name\nFROM    salesperson s\nWHERE   NOT EXISTS (\n    SELECT  s.name\n    FROM    company c, orders o\n    WHERE   s.sales_id = o.sales_id \n        AND c.com_id = o.com_id\n        AND c.name = 'RED'\n    );\n```
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