Hi,
There are more solutions available to get the unique values from the table. It depends on your needs.
This will get unique values from the specific column, because of DISTINCT command:
SELECT DISTINCT brand FROM products ;
This will get other values related to unique values in the specific column, because of GROUP command:
SELECT id, brand FROM products GROUP by brand ;
This will count the values related to unique values in the specific column:
SELECT COUNT(quantity), brand FROM products GROUP by brand ;
This will get only the rows with unique value in the specific column, because of GROUP and HAVING:
SELECT COUNT(quantity), brand FROM products GROUP BY brand HAVING COUNT(quantity) = 1 ;