SQL优化：从一个表中选择不同的

Question

假设我有一个像这样的SQL

select  distinct CUSTOMER_PRODUCT_ORDER as ORDER
from MASTER_LIST 
where PROJECT_ID     = "ABCDD"
 order by   ORDER ASC

如何优化运行此sql的性能？

Answer 1

我认为在大多数情况下，使用group by会更好，更高效：

select  CUSTOMER_PRODUCT_ORDER as ORDER
from MASTER_LIST 
where PROJECT_ID     = "ABCDD"
GROUP BY CUSTOMER_PRODUCT_ORDER
 order by   ORDER ASC