Question

我正在创建一个存储过程，我希望每次匹配时只返回第一条记录而不是匹配的每条记录。

到目前为止，我编写了以下代码：

SELECT
    Tenant.FirstNames AS LeadTenantFirstName, Tenant.LastNames AS LeadTenantLastNames,
    Deposit.CertificateNumber AS DPCNumber

    FROM tblMemberPropertyDepositTenantHistory AS Tenant
    INNER JOIN tblMemberPropertyDeposits AS Deposit 
    ON Tenant.MemberPropertyDepositID = Deposit.MemberPropertyDepositID

问题是它会在查询证书时为每个租户带回一条记录，但我想带回为每个证书创建的第一个租户？

有什么想法吗？

Answer 1

如果我理解你，你需要这样的东西：

;WITH CTE AS
(
    SELECT
        ROW_NUMBER() OVER(PARTITION BY Tenant.MemberPropertyDepositID ORDER BY Tenant.MemberPropertyDepositID) AS RowNbr,
        Tenant.MemberPropertyDepositID,
        Tenant.FirstNames,
        Tenant.LastNames
    FROM
        tblMemberPropertyDepositTenantHistory AS Tenant
)
SELECT
    Tenant.FirstNames AS LeadTenantFirstName, 
    Tenant.LastNames AS LeadTenantLastNames,
    Deposit.CertificateNumber AS DPCNumber
FROM 
    tblMemberPropertyDeposits AS Deposit 
    LEFT JOIN CTE AS Tenant
        ON Tenant.MemberPropertyDepositID=Deposit.MemberPropertyDepositID
        AND Tenant.RowNbr=1

Answer 2

我假设tblMemberPropertyDepositTenantHistory（存款）有一个主键：

SELECT
    Tenant.FirstNames AS LeadTenantFirstName, Tenant.LastNames AS LeadTenantLastNames,
    Deposit.CertificateNumber AS DPCNumber
    FROM tblMemberPropertyDepositTenantHistory AS Tenant
    INNER JOIN tblMemberPropertyDeposits AS Deposit 
    ON Deposit.PrimaryKey = (
        SELECT MIN(tblMemberPropertyDepositTenantHistory.PrimaryKey)
        FROM tblMemberPropertyDepositTenantHistory
        WHERE tblMemberPropertyDepositTenantHistory.MemberPropertyDepositID = 
                Tenant.MemberPropertyDepositID
    )

仅在第一个结果时加入查询

2 个答案: