我有一个 sql 查询问题。我有下表:
╔════╦═══════════════╦═════════════╦══════════╗
║ ID ║ NAME ║ CITY ║ PCNUMBER ║
╠════╬═══════════════╬═════════════╬══════════╣
║ 1 ║ John Doe ║ New York ║ 42 ║
║ 2 ║ John Doe ║ New York ║ 42 ║
║ 3 ║ John Doe ║ New York ║ 42 ║
║ 4 ║ John Doe ║ Los Angeles ║ 42 ║
║ 5 ║ Ellen Ripley ║ Nostromo ║ 2092 ║
║ 6 ║ James T. Kirk ║ Riverside ║ 2233 ║
║ 7 ║ Henry Jones ║ Chicago ║ 1899 ║
╚════╩═══════════════╩═════════════╩══════════╝
现在我想获取具有指定 PCNUMBER(可以大于 1)的行,但它只能为每个唯一的 PCNUMBER 返回 1 个结果
所以让我们假设我想要来自 PCNUMBER 42 和 2092 的数据。结果是:
╔════╦══════════════╦═════════════╦══════════╗
║ ID ║ NAME ║ CITY ║ PCNUMBER ║
╠════╬══════════════╬═════════════╬══════════╣
║ 4 ║ John Doe ║ Los Angeles ║ 42 ║
║ 5 ║ Ellen Ripley ║ Nostromo ║ 2092 ║
╚════╩══════════════╩═════════════╩══════════╝
我已经尝试了很多东西,但我似乎无法做到这一点:(希望你们能帮助我。
如果有人已经有类似的问题,但我找不到,我很抱歉。
最佳答案
SQL Server 支持 Common Table Expression
和 Windowing Functions
.
WITH records
AS
(
SELECT ID, Name, City, PCNUMBER,
ROW_NUMBER() OVER(PARTITION BY PCNUMBER ORDER BY ID DESC) rn
FROM TableName
)
SELECT ID, Name, City, PCNUMBER
FROM records
WHERE rn = 1 AND
PCNUMBER IN (42, 2092)
输出
╔════╦══════════════╦═════════════╦══════════╗
║ ID ║ NAME ║ CITY ║ PCNUMBER ║
╠════╬══════════════╬═════════════╬══════════╣
║ 4 ║ John Doe ║ Los Angeles ║ 42 ║
║ 5 ║ Ellen Ripley ║ Nostromo ║ 2092 ║
╚════╩══════════════╩═════════════╩══════════╝
关于sql - 选择具有最高 ID 和指定列值的行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16239125/