Question

我有这个查询，它给了我需要的结果，但执行速度非常慢。缓慢是因为[Contoso $ Item Ledger Entry]表有~0.6M的记录。请建议如何优化/简化此查询（如果可能）以及我需要具备哪些索引以使其最佳运行。

DECLARE @TempTable TABLE 
(
    Numeris varchar(20)
)
INSERT INTO @TempTable (Numeris)
SELECT No_
FROM [Contoso$Sales Line]
WHERE [Document no_] = 'PP03428'

SELECT I.No_, CASE WHEN 
           ISNULL(ROUND(CAST(SUM(ILE.[Remaining Quantity]) AS float), 2), 0) <
           (SELECT  ISNULL(SUM([Outstanding Quantity]), 0)
            FROM    [Contoso$Sales Line] SL
            WHERE   (SL.No_ = I.No_) 
                AND (SL.[Document type] = 1 OR SL.[Document type] = 2) 
                AND (SL.[DA4 eksportas] = 0) 
                AND (SL.Type = 2)
           ) 
        THEN 0 
        ELSE 
           ISNULL(ROUND(CAST(SUM(ILE.[Remaining Quantity]) AS float), 2) -
           (SELECT  ISNULL(SUM([Outstanding Quantity]), 0)
            FROM    [Contoso$Sales Line] SL
            WHERE   (SL.No_ = I.No_) 
                AND (SL.[Document type] = 1 OR SL.[Document type] = 2) 
                AND (SL.[DA4 eksportas] = 0) 
                AND (SL.Type = 2)), 0
           ) 
    END AS Kiekis
FROM [Contoso$Item] I 
LEFT OUTER JOIN [Contoso$Item Ledger Entry] ILE ON I.No_ = ILE.[Item No_]
WHERE I.No_ IN (SELECT Numeris FROM @TempTable)
GROUP BY I.No_

Answer 1

使用执行计划了解查询的执行方式，并了解查询速度如此之慢的原因。您可以在Contoso $ Item表的No_ Column上添加索引，以避免使用fullscan表

具体的sql查询优化。性能缓慢

1 个答案: