Question

EmployeeID  EmployeeName 
0001          Mr.A  
0002          Mr.A
0003          Mr.A
0004          Mr.B
0005          Mr.B 
0006          Mr.B
0007          Mr.C
0008          Mr.C 
0009          Mr.C

Expected Output 
0001 Mr.A
0004 Mr.B
0007 Mr.c

我希望只看到第一次出现员工ID的唯一员工姓名。

Answer 1

您可以使用row_number()：

执行此操作

select t.*
from (select t.*,
             row_number() over (partition by EmployeeName order by EmployeeId) as seqnum
      from table t
     ) t
where seqnum = 1;

Answer 2

CTE使用ROW_NUMBER

的另一个可能答案

WITH C AS(
    SELECT ROW_NUMBER() OVER (PARTITION BY EmployeeName ORDER BY EmployeeId) AS Rn
   ,EmployeeId
   ,EmployeeName
)
SELECT * FROM C WHERE Rn = 1

如何在oracle中查找组中每个第一行的所有列

2 个答案: