自我完整外部连接的替代方案，以在两个条目之间进行匹配

Question

在我的数据库模型中，我有两个实体：权利和petitrement_data。每个权利都通过增量ID（身份）来确定，并且可以具有多个protement_data条目，每种条目都具有不同的类型-WICH可以是0（每周）或1（每月）（每月）（授权和类型为pk for entitement_data，protiatemention fortialition，protitiond as protitiond as protitiond autitiond autity pk要享有权利表）。对于每个权利，我都需要：

1. 从月度（类型= 1）或每周（type = 0）entitement_data获取第一个非null值，对于给定的entitement_data属性（共享，localtaxrate等...） - 选择的第一部分；
2. 在每月和每周potitement_data条目（Sharespaid_match等）之间获得有关匹配/不匹配的指示 - 选择的最后一部分。

这是我正在使用ATM的查询：

SELECT 
    COALESCE(MD.EntitlementID, WD.EntitlementID) AS EntitlementID,
    COALESCE(MD.LocalTaxRate, WD.LocalTaxRate) AS LocalTaxRate,
    COALESCE(MD.SharesPaid, WD.SharesPaid) AS SharesPaid,
    COALESCE(MD.LocalTaxAmount, WD.LocalTaxAmount) AS LocalTaxAmount,
    COALESCE(MD.LocalTaxEquivalent, WD.LocalTaxEquivalent) AS LocalTaxEquivalent,
    COALESCE(MD.NetReceived, WD.NetReceived) AS NetReceived,
    COALESCE(MD.LocalTaxCurrency, WD.LocalTaxCurrency) AS LocalTaxCurrency,
    COALESCE(MD.Currency, WD.Currency) AS Currency,
    COALESCE(MD.ReleaseDate, WD.ReleaseDate) AS ReleaseDate,
    (
        CASE
            WHEN MD.LocalTaxEquivalent IS NULL OR WD.LocalTaxEquivalent IS NULL THEN NULL
            WHEN MD.LocalTaxEquivalent <> WD.LocalTaxEquivalent THEN 0
            ELSE 1
        END
    ) AS LocalTaxEquivalent_Match,
    (
        CASE
            WHEN MD.NetReceived IS NULL OR WD.NetReceived IS NULL THEN NULL
            WHEN MD.NetReceived <> WD.NetReceived THEN 0
            ELSE 1
        END
    ) AS NetReceived_Match,
    (
        CASE
            WHEN MD.SharesPaid IS NULL OR WD.SharesPaid IS NULL THEN NULL
            WHEN MD.SharesPaid <> WD.SharesPaid THEN 0
            ELSE 1
        END
    ) AS SharesPaid_Match,
    (
        CASE
            WHEN MD.Currency IS NULL OR WD.Currency IS NULL THEN NULL
            WHEN MD.Currency <> WD.Currency THEN 0
            ELSE 1
        END
    ) AS Currency_Match,
    (
        CASE
            WHEN MD.DividendRate IS NULL OR WD.DividendRate IS NULL THEN NULL
            WHEN MD.DividendRate <> WD.DividendRate THEN 0
            ELSE 1
        END
    ) AS DividendRate_Match,
    (
        CASE
            WHEN MD.LocalTaxRate IS NULL OR WD.LocalTaxRate IS NULL THEN NULL
            WHEN MD.LocalTaxRate <> WD.LocalTaxRate THEN 0
            ELSE 1
        END
    ) AS LocalTaxRate_Match
FROM 
    Entitlement_Data MD
    FULL OUTER JOIN Entitlement_Data WD
        ON MD.EntitlementID = WD.EntitlementID
WHERE
    WD.Type = 0 AND MD.Type = 1

有没有办法避免完全外部加入并获得我需要的信息？我评估了一个组的使用，但我似乎没有得到所需的结果。谢谢你。

Answer 1

你为什么不 left join 到“主表” Entitlement 像以下代码：

select
    COALESCE(MD.EntitlementID, WD.EntitlementID) AS EntitlementID,
    COALESCE(MD.LocalTaxRate, WD.LocalTaxRate) AS LocalTaxRate,
    COALESCE(MD.SharesPaid, WD.SharesPaid) AS SharesPaid,
    COALESCE(MD.LocalTaxAmount, WD.LocalTaxAmount) AS LocalTaxAmount,
    COALESCE(MD.LocalTaxEquivalent, WD.LocalTaxEquivalent) AS LocalTaxEquivalent,
    COALESCE(MD.NetReceived, WD.NetReceived) AS NetReceived,
    COALESCE(MD.LocalTaxCurrency, WD.LocalTaxCurrency) AS LocalTaxCurrency,
    COALESCE(MD.Currency, WD.Currency) AS Currency,
    COALESCE(MD.ReleaseDate, WD.ReleaseDate) AS ReleaseDate,
    (
        CASE
            WHEN MD.LocalTaxEquivalent IS NULL OR WD.LocalTaxEquivalent IS NULL THEN NULL
            WHEN MD.LocalTaxEquivalent <> WD.LocalTaxEquivalent THEN 0
            ELSE 1
        END
    ) AS LocalTaxEquivalent_Match,
    (
        CASE
            WHEN MD.NetReceived IS NULL OR WD.NetReceived IS NULL THEN NULL
            WHEN MD.NetReceived <> WD.NetReceived THEN 0
            ELSE 1
        END
    ) AS NetReceived_Match,
    (
        CASE
            WHEN MD.SharesPaid IS NULL OR WD.SharesPaid IS NULL THEN NULL
            WHEN MD.SharesPaid <> WD.SharesPaid THEN 0
            ELSE 1
        END
    ) AS SharesPaid_Match,
    (
        CASE
            WHEN MD.Currency IS NULL OR WD.Currency IS NULL THEN NULL
            WHEN MD.Currency <> WD.Currency THEN 0
            ELSE 1
        END
    ) AS Currency_Match,
    (
        CASE
            WHEN MD.DividendRate IS NULL OR WD.DividendRate IS NULL THEN NULL
            WHEN MD.DividendRate <> WD.DividendRate THEN 0
            ELSE 1
        END
    ) AS DividendRate_Match,
    (
        CASE
            WHEN MD.LocalTaxRate IS NULL OR WD.LocalTaxRate IS NULL THEN NULL
            WHEN MD.LocalTaxRate <> WD.LocalTaxRate THEN 0
            ELSE 1
        END
    ) AS LocalTaxRate_Match
from Entitlement e
left join Entitlement_Data wd on e.id = wd.entitlementID and wd.type = 0
left join Entitlement_Data md on e.id = md.entitlementID and md.type = 1

您可能会限制行 Entitlement 最后一排 Entitlement_Data 表（不关心弱还是每月）使用：

where wd.type is not null or md.type is not null