SQL Server - 如何填充缺失的列值

Question

我有一组包含 2 列的日级别记录:

• 发票日期
• 发票金额

对于少数记录，invoice_amount 的值缺失。

我需要使用以下逻辑填充发票金额为 NULL 的值:

1. 查找下一个可用的invoice_amount(日期晚于空白值记录日期)

2. 对于 invoice_amount 仍为空白(invoice_amount future 日期不存在)的记录，查找最近的 invoice_amount(在日期中)在空白起息日之前)

注意:我们连续多天数据集中的 invoice_amount 为空白:

Answer 1

使用 CROSS APPLY 查找下一个和上一个非空发票金额

update  p
set     Invoice_Amount  = coalesce(nx.Invoice_Amount, pr.Invoice_Amount)
from    Problem p
        outer apply -- Next non null value
        (
            select  top 1 *
            from    Problem x
            where   x.Invoice_Amount    is not null
            and     x.Invoice_Date  > p.Invoice_Date
            order by Invoice_Date
        ) nx
        outer apply -- Prev non null value
        (
            select  top 1 *
            from    Problem x
            where   x.Invoice_Amount    is not null
            and     x.Invoice_Date  < p.Invoice_Date
            order by Invoice_Date desc
        ) pr
where   p.Invoice_Amount    is null

这会更新您的表格。如果需要选择查询，可以轻松修改