Sql server e列顺序。请检查此链接。谢谢-但我不感兴趣的是，在你看来，你是否认为索引2和索引1是多余的。我对一个T-SQL脚本感兴趣，它让我知道一个索引可能与另一个索引冗余。问题不在于我是否相信你。我的问题不是什么构成了冗余索引。如果更多的人只是回答帖子上的问题，而不

---

e列顺序。请检查此链接。谢谢-但我不感兴趣的是，在你看来，你是否认为索引2和索引1是多余的。我对一个T-SQL脚本感兴趣，它让我知道一个索引可能与另一个索引冗余。问题不在于我是否相信你。我的问题不是什么构成了冗余索引。如果更多的人只是回答帖子上的问题，而不是试图回答一个没有被问到的问题，那就太好了。我只是想要一个查询，让我知道哪些索引可能是多余的，然后我们将对每个索引进行评估，以决定采取什么行动。顺便说一句-很好的查询！哇+我要感谢安德奥马尔对这种态度的回答。。。我当然感谢那些比我知道得更多的人花时间指出我的问题中我可能没有考虑或意识到的一个方面。谢谢@AndomarSir，你应该得到一枚奖牌！

Index 1: 'ColumnA', 'ColumnB', 'ColumnC'
Index 2: 'ColumnA', 'ColumnB'

select ColumnC from YourTable where ColumnnA = 12

select * from YourTable where ColumnnA like '%hello%'

;with ind as (
    select  a.object_id
    ,       a.index_id
    ,       cast(col_list.list as varchar(max)) as list
    from    (
            select  distinct object_id
            ,       index_id
            from    sys.index_columns
            ) a
    cross apply
            (
            select  cast(column_id as varchar(16)) + ',' as [text()]
            from    sys.index_columns b
            where   a.object_id = b.object_id
                    and a.index_id = b.index_id
            for xml path(''), type
            ) col_list (list)
)
select  object_name(a.object_id) as TableName
,       asi.name as FatherIndex
,       bsi.name as RedundantIndex
from    ind a
join    sys.sysindexes asi
on      asi.id = a.object_id
        and asi.indid = a.index_id
join    ind b
on      a.object_id = b.object_id
        and a.object_id = b.object_id
        and len(a.list) > len(b.list)
        and left(a.list, LEN(b.list)) = b.list
join    sys.sysindexes bsi
on      bsi.id = b.object_id
        and bsi.indid = b.index_id

WITH IndexColumns AS
(
    SELECT I.object_id AS TableObjectId, OBJECT_SCHEMA_NAME(I.object_id) + '.' + OBJECT_NAME(I.object_id) AS TableName, I.index_id AS IndexId, I.name AS IndexName
        , (IndexUsage.user_seeks + IndexUsage.user_scans + IndexUsage.user_lookups) AS IndexUsage
        , IndexUsage.user_updates AS IndexUpdates

       , (SELECT CASE is_included_column WHEN 1 THEN NULL ELSE column_id END AS [data()]
        FROM sys.index_columns AS IndexColumns
        WHERE IndexColumns.object_id = I.object_id
          AND IndexColumns.index_id = I.index_id
        ORDER BY index_column_id, column_id
        FOR XML PATH('')
       ) AS ConcIndexColumnNrs

       ,(SELECT CASE is_included_column WHEN 1 THEN NULL ELSE COL_NAME(I.object_id, column_id) END AS [data()]
        FROM sys.index_columns AS IndexColumns
        WHERE IndexColumns.object_id = I.object_id
          AND IndexColumns.index_id = I.index_id
        ORDER BY index_column_id, column_id
        FOR XML PATH('')
       ) AS ConcIndexColumnNames

       ,(SELECT CASE is_included_column WHEN 1 THEN column_id ELSE NULL END AS [data()]
        FROM sys.index_columns AS IndexColumns
        WHERE IndexColumns.object_id = I.object_id
        AND IndexColumns.index_id = I.index_id
        ORDER BY column_id
        FOR XML PATH('')
       ) AS ConcIncludeColumnNrs

       ,(SELECT CASE is_included_column WHEN 1 THEN COL_NAME(I.object_id, column_id) ELSE NULL END AS [data()]
        FROM sys.index_columns AS IndexColumns
        WHERE IndexColumns.object_id = I.object_id
          AND IndexColumns.index_id = I.index_id
        ORDER BY column_id
        FOR XML PATH('')
       ) AS ConcIncludeColumnNames
    FROM sys.indexes AS I
       LEFT OUTER JOIN sys.dm_db_index_usage_stats AS IndexUsage
        ON IndexUsage.object_id = I.object_id
          AND IndexUsage.index_id = I.index_id
          AND IndexUsage.Database_id = db_id() 
)
SELECT
  C1.TableName
  , C1.IndexName AS 'Index1'
  , C2.IndexName AS 'Index2'
  , CASE WHEN (C1.ConcIndexColumnNrs = C2.ConcIndexColumnNrs) AND (C1.ConcIncludeColumnNrs = C2.ConcIncludeColumnNrs) THEN 'Exact duplicate'
        WHEN (C1.ConcIndexColumnNrs = C2.ConcIndexColumnNrs) THEN 'Different includes'
        ELSE 'Overlapping columns' END
--  , C1.ConcIndexColumnNrs
--  , C2.ConcIndexColumnNrs
  , C1.ConcIndexColumnNames
  , C2.ConcIndexColumnNames
--  , C1.ConcIncludeColumnNrs
--  , C2.ConcIncludeColumnNrs
  , C1.ConcIncludeColumnNames
  , C2.ConcIncludeColumnNames
  , C1.IndexUsage
  , C2.IndexUsage
  , C1.IndexUpdates
  , C2.IndexUpdates
  , 'DROP INDEX ' + C2.IndexName + ' ON ' + C2.TableName AS Drop2
  , 'DROP INDEX ' + C1.IndexName + ' ON ' + C1.TableName AS Drop1
FROM IndexColumns AS C1
  INNER JOIN IndexColumns AS C2 
    ON (C1.TableObjectId = C2.TableObjectId)
    AND (
         -- exact: show lower IndexId as 1
            (C1.IndexId < C2.IndexId
            AND C1.ConcIndexColumnNrs = C2.ConcIndexColumnNrs
            AND C1.ConcIncludeColumnNrs = C2.ConcIncludeColumnNrs)
         -- different includes: show longer include as 1
         OR (C1.ConcIndexColumnNrs = C2.ConcIndexColumnNrs
            AND LEN(C1.ConcIncludeColumnNrs) > LEN(C2.ConcIncludeColumnNrs))
         -- overlapping: show longer index as 1
         OR (C1.IndexId <> C2.IndexId
            AND C1.ConcIndexColumnNrs <> C2.ConcIndexColumnNrs
            AND C1.ConcIndexColumnNrs like C2.ConcIndexColumnNrs + ' %')
    )
ORDER BY C1.TableName, C1.ConcIndexColumnNrs

WITH IndexSummary AS
(

SELECT DISTINCT sys.objects.name AS [Table Name],
    sys.indexes.name AS [Index Name],
    SUBSTRING((SELECT ', ' +  sys.columns.Name as [text()]
        FROM sys.columns
            INNER JOIN sys.index_columns
                ON sys.index_columns.column_id = sys.columns.column_id
                AND sys.index_columns.object_id = sys.columns.object_id
        WHERE sys.index_columns.index_id = sys.indexes.index_id
            AND sys.index_columns.object_id = sys.indexes.object_id
            AND sys.index_columns.is_included_column = 0
        ORDER BY sys.columns.name
    FOR XML Path('')), 2, 10000) AS [Indexed Column Names],
    ISNULL(SUBSTRING((SELECT ', ' +  sys.columns.Name as [text()]
        FROM sys.columns
            INNER JOIN sys.index_columns
            ON sys.index_columns.column_id = sys.columns.column_id
            AND sys.index_columns.object_id = sys.columns.object_id
        WHERE sys.index_columns.index_id = sys.indexes.index_id
            AND sys.index_columns.object_id = sys.indexes.object_id
            AND sys.index_columns.is_included_column = 1
        ORDER BY sys.columns.name
        FOR XML Path('')), 2, 10000), '') AS [Included Column Names],
    sys.indexes.index_id, sys.indexes.object_id
FROM sys.indexes
    INNER JOIN SYS.index_columns
        ON sys.indexes.index_id = SYS.index_columns.index_id
            AND sys.indexes.object_id = sys.index_columns.object_id
    INNER JOIN sys.objects
        ON sys.OBJECTS.object_id = SYS.indexES.object_id
WHERE sys.objects.type = 'U'
)

SELECT IndexSummary.[Table Name],
    IndexSummary.[Index Name],
    IndexSummary.[Indexed Column Names],
    IndexSummary.[Included Column Names],
    PhysicalStats.page_count as [Page Count],
    CONVERT(decimal(18,2), PhysicalStats.page_count * 8 / 1024.0) AS [Size (MB)],
    CONVERT(decimal(18,2), PhysicalStats.avg_fragmentation_in_percent) AS [Fragment %]
FROM IndexSummary
    INNER JOIN sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, NULL)
       AS PhysicalStats
        ON PhysicalStats.index_id = IndexSummary.index_id
            AND PhysicalStats.object_id = IndexSummary.object_id
WHERE (SELECT COUNT(*) as Computed
        FROM IndexSummary Summary2
        WHERE Summary2.[Table Name] = IndexSummary.[Table Name]
            AND Summary2.[Indexed Column Names] = IndexSummary.[Indexed Column Names]) > 1
ORDER BY [Table Name], [Index Name], [Indexed Column Names], [Included Column Names]

Table Name  Index   Indexed Cols    Included Cols   Pages   Size (MB)   Frag %
My_Table    Indx_1     Col1         Col2, Col3       123      0.96       8.94
My_Table    Indx_2     Col1         Col2, Col3       123      0.96       8.94

/****************************************************************
Description: Script to show Unused Indexes using DMVs
****************************************************************/

SELECT TOP 100
o.name AS ObjectName
, i.name AS IndexName
, i.index_id AS IndexID  
, dm_ius.user_seeks AS UserSeek
, dm_ius.user_scans AS UserScans
, dm_ius.user_lookups AS UserLookups
, dm_ius.user_updates AS UserUpdates
, p.TableRows
, 'DROP INDEX ' + QUOTENAME(i.name) 
+ ' ON ' + QUOTENAME(s.name) + '.' + QUOTENAME(OBJECT_NAME(dm_ius.object_id)) as 'drop statement'
FROM sys.dm_db_index_usage_stats dm_ius  
INNER JOIN sys.indexes i ON i.index_id = dm_ius.index_id AND dm_ius.object_id = i.object_id   
INNER JOIN sys.objects o on dm_ius.object_id = o.object_id
INNER JOIN sys.schemas s on o.schema_id = s.schema_id
INNER JOIN (SELECT SUM(p.rows) TableRows, p.index_id, p.object_id 
                FROM sys.partitions p GROUP BY p.index_id, p.object_id) p 
        ON p.index_id = dm_ius.index_id AND dm_ius.object_id = p.object_id
WHERE OBJECTPROPERTY(dm_ius.object_id,'IsUserTable') = 1
AND dm_ius.database_id = DB_ID()   
AND i.type_desc = 'nonclustered'
AND i.is_primary_key = 0
AND i.is_unique_constraint = 0
ORDER BY (dm_ius.user_seeks + dm_ius.user_scans + dm_ius.user_lookups) ASC
GO