Question

我有此查询，该查询可以正常工作。它返回所有行，并在可能的情况下连接两个表。

现在，我要取消注释最后两行，以便联接的表仅包括IsPrimary = 1的那些记录。（如果IsPrimary = 0，则我不想进行联接，并且列应为null。）

当我取消注释这些行时，它将停止返回Organization表中的所有行。

如何修改此查询以使其正常工作？

Select top (Select ts.MaxRecords
 from TableSettings ts
 where ts.TableName = 'Organization') 
            O.*,
            L.Name,
            ISNULL(C.FirstName, '') + ' ' + IsNull(C.LastName, '') as FullName

        FROM [dbo].[Organization] O 
        left join Location l on l.OrganizationId = o.Id
        left join Contact c on C.LocationId = l.Id

        WHERE
        O.TenantId = @tenantId and
        (@id IS NULL OR O.Id  = @Id) AND
        (@name IS NULL OR O.Name LIKE '%' + trim(@Name) + '%') AND
        (@organizationTypeId IS NULL OR O.OrganizationTypeId = @organizationTypeId) 
        --and l.IsPrimary = 1 and
        --C.IsPrimary = 1

Answer 1

将您的条件从where子句移至联接。

对于内部联接，它们是等效的，但是对于左联接，它是空结果与无结果之间的差异。

Answer 2

 Select top (Select ts.MaxRecords
 from TableSettings ts
 where ts.TableName = 'Organization') 
        O.*,
        L.Name,
        ISNULL(C.FirstName, '') + ' ' + IsNull(C.LastName, '') as FullName

    FROM [dbo].[Organization] O 
    left join Location l on l.OrganizationId = o.Id and l.IsPrimary = 1
    left join Contact c on C.LocationId = l.Id and C.IsPrimary = 1

    WHERE
    O.TenantId = @tenantId and
    (@id IS NULL OR O.Id  = @Id) AND
    (@name IS NULL OR O.Name LIKE '%' + trim(@Name) + '%') AND
    (@organizationTypeId IS NULL OR O.OrganizationTypeId = @organizationTypeId)

如何将过滤器添加到联接表

2 个答案: