SQL SERVER solution using EXCEPT
SELECT name\nFROM SalesPerson\nEXCEPT\nSELECT s.name\nFROM Orders o \nJOIN Company c ON o.com_id = c.com_id\nJOIN SalesPerson s ON o.sales_id = s.sales_id\nWHER
SELECT name\nFROM SalesPerson\nEXCEPT\nSELECT s.name\nFROM Orders o \nJOIN Company c ON o.com_id = c.com_id\nJOIN SalesPerson s ON o.sales_id = s.sales_id\nWHERE c.name = \'RED\'
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