我有多个查询，OUTER APPLY但所有表在连接列上都有主键（所以这里使用聚集索引）所以我不知道如何进一步优化这个查询。此外，这里不可能使用索引视图，因为它们禁止使用ORDER BYand 。TOP
所以我有
Fields具有Id主键和大量其他列的表。WeatherHistory具有复杂主键 (FieldIdand[Date]) 和很多列的表，NdviImageHistory具有FieldId,[Date],[Base64]列（复杂主键FieldId和[Date]）的表[Base64]存储图像 base64，NaturalColorImageHistory具有FieldId,[Date],[Base64]列（复杂主键FieldId和[Date]）的表[Base64]存储图像 base64，NdviHistory带有FieldId,[Date],MeanNdvi列的表（复杂的主键FieldId和[Date]），FieldSeasonHistory具有Field,StartDate,EndDate列的表（复杂主键FieldId和[Date]）。
我的查询
SELECT Fields.*,
WeatherHistory.TempSumC AS CurrentTempSumC,
TempSumF AS CurrentTempSumF,
PrecipitationSumMm AS CurrentPrecipitationSumMm,
nih.[Base64] AS CurrentNdviImageBase64,
ncih.[Base64] AS CurrentNaturalColorImageBase64,
MeanNdvi AS CurrentMeanNdvi,
IsOpenSeason
FROM Fields
LEFT JOIN WeatherHistory ON FieldId = Id AND [Date] = CAST(GETUTCDATE() AS DATE)
OUTER APPLY
(
SELECT TOP 1 [Base64]
FROM NdviImageHistory
WHERE FieldId = Id
ORDER BY [Date] DESC
) nih
OUTER APPLY
(
SELECT TOP 1 [Base64]
FROM NaturalColorImageHistory
WHERE FieldId = Id
ORDER BY [Date] DESC
) ncih
OUTER APPLY
(
SELECT TOP 1 MeanNdvi
FROM NdviHistory
WHERE FieldId = Id
ORDER BY [Date] DESC
) nh
OUTER APPLY
(
SELECT TOP 1 CASE WHEN EndDate IS NULL THEN 1 ELSE 0 END AS IsOpenSeason
FROM FieldSeasonHistory
WHERE FieldId = Id
ORDER BY [StartDate] DESC
) fsh
WHERE UserId = (SELECT Id FROM Users WHERE Email = @email) AND IsArchived = 0
我没有创建任何索引，因为我认为自动生成的集群索引（基于主键）应该足够了（但我可能是错的）。此查询执行大约 15 秒，但我想减少查询时间。
编辑：添加索引UserId和IsArchived表的列Fields。查询执行计划：
** 编辑 2：** 统计数据：
SQL Server parse and compile time:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server parse and compile time:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 0 ms.
(13 row(s) affected)
Table 'FieldSeasonHistory'. Scan count 13, logical reads 26, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'NdviHistory'. Scan count 13, logical reads 26, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'NaturalColorImageHistory'. Scan count 13, logical reads 26, physical reads 0, read-ahead reads 0, lob logical reads 604, lob physical reads 0, lob read-ahead reads 0.
Table 'NdviImageHistory'. Scan count 13, logical reads 39, physical reads 0, read-ahead reads 0, lob logical reads 68, lob physical reads 0, lob read-ahead reads 0.
Table 'WeatherHistory'. Scan count 0, logical reads 39, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Users'. Scan count 0, logical reads 228, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Fields'. Scan count 1, logical reads 19, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
(1 row(s) affected)
SQL Server Execution Times:
CPU time = 15 ms, elapsed time = 16 ms.
SQL Server parse and compile time:
CPU time = 0 ms, elapsed time = 0 ms.
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 0 ms.