Question

我的源表看起来像这样

cust_id  cust_name
1        John Smith
1        John K Smith
2        Mary B Snow
2        Mary Snow

我想返回

cust_id  cust_name
1        John Smith
2        Mary B Snow

其中一个cust_name值不优先于另一个;我只想要每个cust_id一行，并附加一个任意的cust_name。

我正在使用

select cust_id, cust_name from customers
qualify 1 = row_number() over (partition by cust_id order by cust_name desc)

但由于order by子句的原因，我无法在子查询中使用它。

有没有办法可以在没有（概念上不必要的）排序的情况下做到这一点？

Answer 1

您必须在SELECT NULL子句中使用ORDER BY。因此它不会改变顺序，Row_Number将按预期工作

试试这个

SELECT cust_id, cust_name FROM
(
  SELECT cust_id, cust_name ,ROW_NUMBER() OVER (PARTITION  BY cust_id ORDER BY  (SELECT NULL)) RN
  FROM customers
)Tmp WHERE RN = 1

Answer 2

select cust_id, min(cust_name) 
from customers 
group by cust_id

Answer 3

如果不需要订购，只需运行：

SELECT cust_id, MAX(cust_name)
FROM customers
GROUP BY cust_id

Answer 4

这应该有效

select cust_id, 
min(cust_name) as cust_name
from customers 
group by cust_id

按组排序选择最高记录而不按顺序

4 个答案: