SQL优化:选择一个表不同

Question

假设我有一个这样的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，

分组会更好，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