sql - SQL优化：从一个表中选择不同的

Question

假设我有这样的 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，性能更高：

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