table 中有重复的记录，我们只需要 select 使用 group by 或 window 函数 sql 中的最新记录

Question

在table中有重复的记录，我们需要在sql[=16]中使用group by或window函数只select根据日期的最新记录=]

| emp_id | emp_name | department| create_date
+--------------------------------------------+
|   1    |  Nilesh  |    10     |  1-JAN-22  |
|   1    |  Nilesh  |    11     |  5-JAN-22  |
|   2    |  Rohit   |    12     |  1-JAN-22  | 
|   2    |  Rohit   |    13     |  5-JAN-22  |

代码：

select * from (
    select emp_id, emp_name, create_date, department, row_number() over
        (partition by date(create_date) 
         order by create_date desc) as row_num 
    from emp1) 
where row_num = 1
order by create_date;```

Answer 1

您可以像这样简单地使用 GROUP BY

SELECT 
    emp_id, emp_name, department, MAX(create_date)
FROM 
    emp1
GROUP BY 
    emp_id, emp_name, department

如果你想使用 ROW_NUMBER 你必须 PARTITION BY id

SELECT 
    emp_id, emp_name, department, create_date
FROM 
(
    SELECT 
        emp_id, emp_name, department, create_date, ROW_NUMBER () OVER (partition by emp_id order by create_date desc) as num
    FROM 
        emp1
) sub_query
where num = 1

table 中有重复的记录，我们只需要 select 使用 group by 或 window 函数 sql 中的最新记录

There are duplicate records in table, we need to select only the latest records as per date using group by or window function in sql

sql

database

group-by

window-functions