如何降低非聚集索引扫描成本

Question

I have a query that is running on MS Access and the NonClustered scan in the execution plan has a cost of 100% in our SSMS. This query has the second highes processing time, which means this reduces our applications speed when this is executed. I am wondering if anyone knows what i can do to reduce the cost% for this Nonclustered index? Below is the query that is calling this table, the indexed for this table and the execution plan.

SELECT "ContactID" ,"ContactName"  FROM "dbo"."Contacts" 

Here the execution plan:

Here are the indexes that are in the table that this slow query is referencing:

Answer 1

您的查询没有WHERE子句，因此无法避免扫描整个表，因为您要求返回每一行。