Question

我有两个（简化的）表/类设置如下：

public class OrderHeader
{
    public OrderHeader()
    {
        Details = new HashSet<OrderDetail>();
    }

    [Key]
    public int TransactionId { get; set; }
    public string CustomerName { get; set; }
    public virtual ICollection<OrderDetail> Details { get; set; }
}

public class OrderDetail
{
    [Key]
    public int DetailId { get; set; }
    public int ItemId { get; set; }
    public int QuantityOrdered { get; set; }
    public int QuantityShipped { get; set; }
    public int QuantityRemaining { get; set; }
    public int TransactionId { get; set; }

    [ForeignKey("TransactionId")]
    public virtual OrderHeader Header { get; set; }
}

我正在尝试创建一个返回的视图：

TransactionId
按OrderHeader列Number of Details
OrderHeader的详细信息，其中QuantityRemaining等于零为Completed
OrderHeader名为Partially Shipped的详细信息，其中QuantityShipped大于零但小于QuantityOrdered

我已经尝试查询OrderHeader和OrderDetails表，并尝试为我想要的每个列进行子查询，但我最终获得了多行TransactionId。当我使用DISTINCT选择时，数字与我所知的正确无关。

虽然承认这完全是可怜的，但我只能用两列来获得部分但准确的结果集：

    SELECT
        TransactionId,
        COUNT(*) AS [Number of Details]
    FROM OrderDetails
    GROUP BY TransactionID

但我无法使用其他两个专栏。

Answer 1

这样的东西？

SELECT
  TransactionId,
  COUNT(*) AS [Number of Details],
  Sum(CASE WHEN QuantityRemaining = 0 THEN 1 ELSE 0 END) AS [Completed],
  Sum(CASE WHEN QuantityShipped > 0 AND QuantityShipped < QuantityOrdered THEN 1 ELSE 0 END) AS [Partially Shipped]
FROM OrderDetails
GROUP BY TransactionID

如何使用SQL创建主/明细表的摘要视图

1 个答案: