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I have a table 1 where I need to join with other 4 tables. Can I write the same query using subqueries? Because if I am using below query it is taking long time (more than 40 mins) for running. Is there any other way for this?

select T1.ID as IID, T2.Prokey as Pro, T3.pname as IType, T4.pname as Status, T5.pname as Res
from table1 T1
INNER JOIN Table2 T2 on T1.pro = T2.ID
INNER JOIN table3 T3 on T1.itype =T3.ID
INNER JOIN table4 T4 on T1.itatus = T4.ID
INNER JOIN Table5 T5 on T1.Res = T5.ID
group by T2.ID, convert(nvarchar(max), T2.ID), T1.ID, T1.Pkey, T3.pname, T4.pname, T5.pname
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3 回答 3

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这可以让您对所需的索引有一个基本的了解。尝试查看您的主键。

    SELECT CAST(SERVERPROPERTY('ServerName') AS [nvarchar](256)) AS 

[SQLServer]
    ,db.[database_id] AS [DatabaseID]
    ,db.[name] AS [DatabaseName]
    ,id.[object_id] AS [ObjectID]
    ,id.[statement] AS [FullyQualifiedObjectName]
    ,id.[equality_columns] AS [EqualityColumns]
    ,id.[inequality_columns] AS [InEqualityColumns]
    ,id.[included_columns] AS [IncludedColumns]
    ,gs.[unique_compiles] AS [UniqueCompiles]
    ,gs.[user_seeks] AS [UserSeeks]
    ,gs.[user_scans] AS [UserScans]
    ,gs.[last_user_seek] AS [LastUserSeekTime]
    ,gs.[last_user_scan] AS [LastUserScanTime]
    ,gs.[avg_total_user_cost] AS [AvgTotalUserCost]
    ,gs.[avg_user_impact] AS [AvgUserImpact]
    ,gs.[system_seeks] AS [SystemSeeks]
    ,gs.[system_scans] AS [SystemScans]
    ,gs.[last_system_seek] AS [LastSystemSeekTime]
    ,gs.[last_system_scan] AS [LastSystemScanTime]
    ,gs.[avg_total_system_cost] AS [AvgTotalSystemCost]
    ,gs.[avg_system_impact] AS [AvgSystemImpact]
    ,gs.[user_seeks] * gs.[avg_total_user_cost] * (gs.[avg_user_impact] * 0.01) AS [IndexAdvantage]
    ,'CREATE INDEX [Missing_IXNC_' + OBJECT_NAME(id.[object_id], db.[database_id]) + '_' + REPLACE(REPLACE(REPLACE(ISNULL(id.[equality_columns], ''), ', ', '_'), '[', ''), ']', '') + CASE
        WHEN id.[equality_columns] IS NOT NULL
            AND id.[inequality_columns] IS NOT NULL
            THEN '_'
        ELSE ''
        END + REPLACE(REPLACE(REPLACE(ISNULL(id.[inequality_columns], ''), ', ', '_'), '[', ''), ']', '') + '_' + LEFT(CAST(NEWID() AS [nvarchar](64)), 5) + ']' + ' ON ' + id.[statement] + ' (' + ISNULL(id.[equality_columns], '') + CASE
        WHEN id.[equality_columns] IS NOT NULL
            AND id.[inequality_columns] IS NOT NULL
            THEN ','
        ELSE ''
        END + ISNULL(id.[inequality_columns], '') + ')' + ISNULL(' INCLUDE (' + id.[included_columns] + ')', '') AS [ProposedIndex]
    ,CAST(CURRENT_TIMESTAMP AS [smalldatetime]) AS [CollectionDate]
FROM [sys].[dm_db_missing_index_group_stats] gs WITH (NOLOCK)
INNER JOIN [sys].[dm_db_missing_index_groups] ig WITH (NOLOCK)
    ON gs.[group_handle] = ig.[index_group_handle]
INNER JOIN [sys].[dm_db_missing_index_details] id WITH (NOLOCK)
    ON ig.[index_handle] = id.[index_handle]
INNER JOIN [sys].[databases] db WITH (NOLOCK)
    ON db.[database_id] = id.[database_id]
WHERE id.[database_id] > 4 -- Remove this to see for entire instance

ORDER BY [IndexAdvantage] DESC
OPTION (RECOMPILE);
于 2016-11-30T15:50:32.683 回答
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下面是 SQL 语句：

-- CREATE TABLE 1 INDEXES 

CREATE NONCLUSTERED INDEX IX_Table1_pro
ON Table1 (pro) 

CREATE NONCLUSTERED INDEX IX_Table1_itype 
ON Table1 (itype) 

CREATE NONCLUSTERED INDEX IX_Table1_itatus
ON Table1 (itatus) 

CREATE NONCLUSTERED INDEX IX_Table1_Res
ON Table1 (Res) 

-- CREATE TABLE 2 INDEXES 

CREATE NONCLUSTERED INDEX IX_Table2_ID
ON Table2 (ID) 

-- CREATE TABLE 3 INDEXES 

CREATE NONCLUSTERED INDEX IX_Table3_ID
ON Table3 (ID) 

-- CREATE TABLE 4 INDEXES 

CREATE NONCLUSTERED INDEX IX_Table4_ID
ON Table4 (ID) 

-- CREATE TABLE 5 INDEXES 

CREATE NONCLUSTERED INDEX IX_Table5_ID
ON Table5 (ID)
于 2016-11-30T16:05:29.480 回答
0

首先，在table1中创建4个索引：

IX_Table1_pro , IX_Table1_itype , IX_Table1_itatus , IX_Table1_Res 使用这个脚本（XXX 是列名）

CREATE NONCLUSTERED INDEX IX_Table1_XXX  ON Table1 (XXX)

然后使用列 ID 在其他表中创建索引

于 2016-11-30T15:55:30.617 回答