tsql - 从组中选择具有特定值的行？

Question

从下表中，如果 Project.Date 组有失败和成功，我想保留失败行，但如果是单行（与其他行一样），则无论状态如何，都保留该行。例如，我想保留第一行，丢弃第二行并将其余的保留在下表中。

╔═════════╦══════════╦═════════╗
║ PROJECT ║   DATE   ║ STATUS  ║
╠═════════╬══════════╬═════════╣
║ HLM     ║ 20130422 ║ Fail    ║
║ HLM     ║ 20130422 ║ Success ║
║ HLM     ║ 20130423 ║ Fail    ║
║ HLM     ║ 20130424 ║ Success ║
║ HLM     ║ 20130425 ║ Fail    ║
║ HLM     ║ 20130426 ║ Success ║
╚═════════╩══════════╩═════════╝

Answer 1

WITH records
AS
(
    SELECT  [Project], [Date], [Status],
            ROW_NUMBER() OVER (PARTITION BY [Project], [Date]
                                ORDER BY [Status]) rn
    FROM    TableName
)
SELECT  [Project], [Date], [Status]
FROM    records
WHERE   rn = 1

• SQLFiddle 演示

输出

╔═════════╦══════════╦═════════╗
║ PROJECT ║   DATE   ║ STATUS  ║
╠═════════╬══════════╬═════════╣
║ HLM     ║ 20130422 ║ Fail    ║
║ HLM     ║ 20130423 ║ Fail    ║
║ HLM     ║ 20130424 ║ Success ║
║ HLM     ║ 20130425 ║ Fail    ║
║ HLM     ║ 20130426 ║ Success ║
╚═════════╩══════════╩═════════╝