Question

我无法编写SQL代码来检索order_number列中的最大数量。注意visit_number是group包含多个记录，我想要order_number列的最大值。

visit_number , Order_number , NAME
111          ,     1        , 001
111          ,     2        , 001
111          ,     3        , 001
222          ,     1        , 252
222          ,     2        , 252 
003          ,     1        , 121
003          ,     2        , 121

我希望结果如下所示：

111          ,     3        , 001
222          ,     2        , 252 
003          ,     2        , 121

这是我的查询

SELECT VISIT_NUMBER , MAX(ORDER_NUMBER) , NAME
from table
group by ( visit_number , name )

Answer 1

使用GROUP BY和MAX功能。

SELECT visit_number, MAX(Order_number), NAME
FROM yourtable
GROUP BY visit_number, NAME

Answer 2

使用子查询加入表，该子查询返回每个visit_number及其最大order_number：

SELECT distinct t1.*
FROM tablename t1
  JOIN (select visit_number, MAX(Order_number) as max_Order_number
        from tablename group by visit_number) as t2
  ON t1.visit_number = t2.visit_number and t1.Order_number = t2.max_Order_number

（如果最大订单号有多个不同的名称，将返回所有行。）

Answer 3

select VISIT_NUMBER, ORDER_NUMBER, NAME
from (
select VISIT_NUMBER, ORDER_NUMBER, NAME, row_number() over(partition by VISIT_NUMBER order by ORDER_NUMBER desc) as ORDER_DESC
from TABLE
)
where ORDER_DESC = 1

这将返回每个VISIT_NUMBER的最大值，即使NAME更改

检索oracle DB的每组记录的最大数量

3 个答案: