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[英]SQL query using ROW_NUMBER() OVER PARTITION BY with Dynamic Columns
[英]SQL most recent using row_number() over partition
我正在處理一些網絡點擊數據,我只是在尋找帶有訪問過的 user_id(通過時間戳)的最新 page_name。 使用下面的代碼,user_id 重復,page_name 顯示,按降序排序。 但是,我只希望最近點擊始終 = 1。完成后的查詢將用作更大查詢中的子查詢。
這是我當前的代碼:
SELECT user_id,
page_name,
row_number() over(partition by session_id order by ts desc) as recent_click
from clicks_data;
user_id | page_name | recent_click
--------+-------------+--------------
0001 | login | 1
0001 | login | 2
0002 | home | 1
您應該能夠將查詢移動到子查詢並添加where
條件:
SELECT user_id, page_name, recent_click
FROM (
SELECT user_id,
page_name,
row_number() over (partition by session_id order by ts desc) as recent_click
from clicks_data
) T
WHERE recent_click = 1
您應該將row_number()
函數移動到子查詢中,然后在外部查詢中對其進行過濾。
像這樣的東西:
SELECT * FROM (
SELECT
[user_id]
,[page_name]
,ROW_NUMBER() OVER (PARTITION BY [session_id]
ORDER BY [ts] DESC) AS [recent_click]
FROM [clicks_data]
)x
WHERE [recent_click] = 1
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