Question

我有这个查询来显示我想要的数据。但它给了我错误[Err] 21000-[SQL Server]子查询返回了多个值。当子查询遵循=，！=，<，<=，>，> =或将子查询用作表达式时，不允许这样做。

数据：MCRX-MX023-LF-KGX，但是当我输入其他数据时没有错误

这是Sql Server 2008

SELECT
    *
FROM
    (
        SELECT
            SupplierID,
            CurrencyAP AS Currency,
            (
                SELECT
                    UnitPrice
                FROM
                    Ms_PartPriceSupplier
                WHERE
                    SupplierID = x.SupplierID
                AND PartID = x.PartID
                AND LastUpdateDate = x.Tgl
            ) AS Price,
            PartID,
            (
                SELECT
                    PartnerName
                FROM
                    Ms_Partner
                WHERE
                    PartnerID = x.SupplierID
            ) SupplierName
        FROM
            (
                SELECT
                    PartID,
                    SupplierID,
                    CurrencyAP,
                    MAX (LastUpdateDate) AS Tgl
                FROM
                    Ms_PartPriceSupplier
                WHERE
                    PartID = 'MCRX-MX023-LF-KGX'
                GROUP BY
                    PartID,
                    SupplierID,
                    CurrencyAP
            ) x
    ) y
UNION ALL
    SELECT
        PartnerID AS SupplierID,
        '' AS Currency,
        0 AS Price,
        '' AS PartID,
        PartnerName AS SupplierName
    FROM
        Ms_Partner
    WHERE
        PartnerID NOT IN (
            SELECT DISTINCT
                SupplierID
            FROM
                Ms_PartPriceSupplier
            WHERE
                PartID = 'MCRX-MX023-LF-KGX'
        )

Answer 1

查询中Price和/或SupplierName列的SELECT子查询返回多个值。他们应该只返回一个值（每行）。

您可以在这些子查询中提供TOP（1）或在其WHERE / HAVING子句中调整条件。

Answer 2

您的某些子查询返回的值大于1

train_config:{


  freeze_variables: ".*FirstStageFeatureExtractor/resnet_v1_50/conv1.*"
  freeze_variables: ".*FirstStageFeatureExtractor/resnet_v1_50/block1.*"
  freeze_variables: ".*FirstStageFeatureExtractor/resnet_v1_50/block2.*"
  freeze_variables: ".*FirstStageFeatureExtractor/resnet_v1_50/block3.*"


}

在设备中根据需要添加SELECT UnitPrice FROM Ms_PartPriceSupplier WHERE SupplierID = x.SupplierID AND PartID = x.PartID AND LastUpdateDate = x.Tgl SELECT PartnerName FROM Ms_Partner WHERE PartnerID = x.SupplierID或某些聚合功能，例如TOP (1)，MIN，例如：

MAX

Answer 3

错误消息很清楚。当您使用子查询代替表而不是值时，必须确保仅返回一个值，否则将收到此错误消息。

对查询的进一步调查显示，您...做错了。例如，

    (
        SELECT
            PartnerName
        FROM
            Ms_Partner
        WHERE
            PartnerID = x.SupplierID
    ) SupplierName

在这里您似乎想要获取与每个SupplierID关联的名称。您不应该以这种方式在SELECT部分中进行子查询。请记住：首先评估FROM，然后评估WHERE，然后评估SELECT。您实际上在这里指示数据库的是尝试返回一个SINGLE值作为SupplierName：仅当您的查询中只有一个SupplierID时，这才起作用。

您需要开始思考联接。这是您应该如何编写查询的方法：

SELECT
    *
FROM
    (
        SELECT
            SupplierID,
            CurrencyAP AS Currency,
            Ms_PartPriceSupplier.UnitPrice AS Price,
            PartID,
            Ms_Partner.PartnerName as SupplierName
        FROM
            (
                SELECT
                    PartID,
                    SupplierID,
                    CurrencyAP,
                    MAX (LastUpdateDate) AS Tgl
                FROM
                    Ms_PartPriceSupplier
                WHERE
                    PartID = 'MCRX-MX023-LF-KGX'
                GROUP BY
                    PartID,
                    SupplierID,
                    CurrencyAP
            ) x
            inner join Ms_Partner on PartnerID = x.SupplierID
            inner join Ms_PartPriceSupplier on SupplierID = x.SupplierID AND PartID = x.PartID AND LastUpdateDate = x.Tgl
    ) y
UNION ALL
    SELECT
        PartnerID AS SupplierID,
        '' AS Currency,
        0 AS Price,
        '' AS PartID,
        PartnerName AS SupplierName
    FROM
        Ms_Partner
    WHERE
        PartnerID NOT IN (
            SELECT DISTINCT
                SupplierID
            FROM
                Ms_PartPriceSupplier
            WHERE
                PartID = 'MCRX-MX023-LF-KGX'
        )

子查询返回的值超过1。如何解决？

3 个答案: