SELECT
[Total Cost] = ROUND(avg_total_user_cost * avg_user_impact * (user_seeks + user_scans),0)
, avg_user_impact
, TableName = statement
, [EqualityUsage] = equality_columns
, [InequalityUsage] = inequality_columns
, [Include Cloumns] = included_columns
FROM sys.dm_db_missing_index_groups g
INNER JOIN sys.dm_db_missing_index_group_stats s
ON s.group_handle = g.index_group_handle
INNER JOIN sys.dm_db_missing_index_details d
ON d.index_handle = g.index_handle
ORDER BY [Total Cost] DESC;
SELECT
c.name AS databasename,
c.equality_columns,
c.inequality_columns,
c.included_columns,
c.statement AS tablename,
c.avg_total_user_cost AS ReducingTheAverageCost,
c.avg_user_impact AS PercentageOfRevenue,
c.last_user_seek AS TheLastTimeTheEffectAfterUse,
c.unique_compiles
FROM (SELECT
a.name,
b.*
FROM (SELECT
d.*,
s.avg_total_user_cost,
s.avg_user_impact,
s.last_user_seek,
s.unique_compiles
FROM sys.dm_db_missing_index_group_stats s,
sys.dm_db_missing_index_groups g,
sys.dm_db_missing_index_details d
WHERE s.group_handle = g.index_group_handle
AND d.index_handle = g.index_handle
AND s.avg_user_impact > 90
--AND s.unique_compiles > 10
--order by s.avg_user_impact desc
) b,
sys.databases a
WHERE a.database_id = b.database_id) c
WHERE c.name = 'xxxxx'
ORDER BY PercentageOfRevenue DESC, unique_compiles DESC
当然，按照上面的规则建立索引，不过还是要建立尽量少的索引，因为索引建多了，会导致insert、update等操作的开销增大，降低性能。
还有，在建立了索引后，可以通过如下的查询，来查询索引的使用的情况：
select *
from sys.dm_db_index_usage_stats
如果，对index_seek的次数，很小，那么可以考虑删除这个索引，再尝试建立其他的索引，如此多次，就能建立真正让查询使用的索引，让这些索引都能发挥作用，同时尽量减少索引的数量
