如何使用 SQL Query 获取 Max Date、Min Date 和 Null 列是否为空

Question

我在创建 SQL 查询时遇到了一些麻烦。我想用所有列和行查询表中的记录。

我使用下面的select 查询。它实际上反映了我想要的记录，但唯一的问题是它只显示了 19 列中的 3 列。它只显示Barangay、Wentoff 和Restored 的列。我想要的是显示相应结果的所有 19 列。

这是我的 SQL 代码：

SELECT Barangay, MIN(wentoff) as Wentoff, 
CASE WHEN MAX(CASE WHEN Restored IS NULL THEN 1 ELSE 0 END) = 0 THEN MAX(Restored) End 
FROM ReportforValidation 
GROUP BY Barangay

请查看我查询的当前结果：

我需要显示的表格的字段：

Answer 1

你可以使用窗口函数代替group by:

SELECT  Barangay, 
        MIN(wentoff) OVER (
            PARTITION BY Barangay
        ) as Wentoff, 
        FIRST_VALUE(Restored) OVER (
            PARTITION BY Barangay 
            ORDER BY CASE WHEN Restored IS NULL THEN 0 ELSE 1 END, 
                     Restored DESC
        ),
        ReportNo,
        area,
        calamaty,
        response
FROM    ReportforValidation;

将您希望在输出中包含的所有列添加到select 子句。

如果您不想要所有行，而只想要那些具有“第一个值”Restored 的行，那么还要选择分区的行号并将其包装在 select 中过滤第 1 行的查询：

SELECT *
FROM   (
    SELECT  Barangay, 
            MIN(wentoff) OVER (
                PARTITION BY Barangay
            ) as Wentoff, 
            FIRST_VALUE(Restored) OVER (
                PARTITION BY Barangay 
                ORDER BY CASE WHEN Restored IS NULL THEN 0 ELSE 1 END, 
                         Restored DESC
            ) Restored,
            ROW_NUMBER() OVER (
                PARTITION BY Barangay 
                ORDER BY CASE WHEN Restored IS NULL THEN 0 ELSE 1 END, 
                         Restored DESC
            ) as rn,
            ReportNo,
            area,
            calamaty,
            response
    FROM    ReportforValidation
    ) as all_rows
WHERE rn = 1;

Answer 2

@trincot 先生，您的代码完美运行我对此代码唯一担心的是 rn 也出现在列中。怎么隐藏？
选择 * 从 （ 选择描笼涯， MIN(wentoff) OVER ( Barangay的分区 ) 作为温托夫， FIRST_VALUE（已恢复）超过（ Barangay的分区 ORDER BY CASE WHEN Restored IS NULL THEN 0 ELSE 1 END, 恢复 DESC ) 恢复， ROW_NUMBER() OVER ( Barangay的分区 ORDER BY CASE WHEN Restored IS NULL THEN 0 ELSE 1 END, 恢复 DESC ) 作为 rn, 报告否， 区域， 灾难， 回复 FROM 验证报告 ) 作为 all_rows 其中 rn = 1;