Question

我尝试对四列进行排名。它们需要按员工ID分组，然后按订单编号从低到高列出。然后，当一切正常时，我实际上是在尝试按该顺序排列城市的排名。如果在同一座城市的同一城市之后列出了同一名员工，那么我希望那些排名相同。

下表的示例如下。顺序是正确的，但是排名不符合我要尝试的水平。

Name            Employee_ID     Order_Number     City       Rank   
John               1                1            Boston       1  
John               1                2            Boston       2  
Will               2                1            Peabody      1  
Will               2                2            Weston       2   
Will               2                3            Newton       3



select Name, Employee_ID, Order_Number, City,
dense_rank() over(partition by Employee_ID order by Order_Number) as rank
from #Employee

我实际希望的结果是：

Name            Employee_ID     Order_Number     City       Rank   
John               1                1            Boston       1  
John               1                2            Boston       1  
Will               2                1            Boston       1  
Will               2                2            Weston       2   
Will               2                3            Newton       3

然后，我最终将删除重复的城市，最终得到：

Name            Employee_ID     Order_Number     City       Rank   
John               1                1            Boston       1  
Will               2                1            Boston       1  
Will               2                2            Weston       2   
Will               2                3            Newton       3

Answer 1

您可以尝试以下脚本来获取所需的输出。

this.txtDefault.ShouldReturn += (textField) => {
textField.ResignFirstResponder();
return true;
};

结果集的输出是-

SELECT Name, Employee_ID, Order_Number, City ,
ROW_NUMBER() OVER (PARTITION BY Employee_ID ORDER BY Order_Number) rank
(
    select Name, Employee_ID, Order_Number, City,
    dense_rank() over(partition by Employee_ID,city order by Order_Number) as rank
    from #Employee
)A
WHERE rank = 1

在Fiddle上检查脚本的输出。

Answer 2

您可以使用Bitmap Heap Scan on cache (cost=12.15..1387.51 rows=364 width=585) (actual time=53.794..87.802 rows=71634 loops=1) Recheck Cond: ((((data -> 'Info'::text) ->> 'Date'::text) >= '2018-01-01'::text) AND (((data -> 'Info'::text) ->> 'Date'::text) <= '2020-12-01'::text) AND (((data -> 'Info'::text) ->> 'Condition'::text) = '3'::text)) Heap Blocks: exact=16465 -> Bitmap Index Scan on cache_data_index (cost=0.00..12.06 rows=364 width=0) (actual time=51.216..51.216 rows=71634 loops=1) Index Cond: ((((data -> 'Info'::text) ->> 'Date'::text) >= '2018-01-01'::text) AND (((data -> 'Info'::text) ->> 'Date'::text) <= '2020-12-01'::text)) Planning Time: 0.247 ms Execution Time: 90.586 ms检查以前的城市是否相同。如果先前的城市不同或为空，则我们按原样进行排名；如果城市相同，则排名-1为我们提供与上一行相同的数字。 Demo

LAG()

如何按一列排序，但如何基于非数字的另一列进行排序？

2 个答案: