Elegant Select Solution
\nSELECT \n\tproduct_id,\n\tproduct_name \nFROM\n\tProduct\nWHERE product_id NOT IN\n\t(SELECT\n\t\tproduct_id\n\tFROM \n\t\tSales\n\tWHERE\n\t\tsale_date \n   
```\nSELECT \n\tproduct_id,\n\tproduct_name \nFROM\n\tProduct\nWHERE product_id NOT IN\n\t(SELECT\n\t\tproduct_id\n\tFROM \n\t\tSales\n\tWHERE\n\t\tsale_date \n    NOT BETWEEN \n     \'2019-01-01\' AND \'2019-03-31\')\n```
[]