查找具有連續日期的行

Question

是否可以知道哪位顧客連續 3 天光顧了酒吧？ （約翰在我的情況下）

提前致謝

名稱	年齡	日期	數量
保羅	12	2021-12-01	20
約翰	19	2021-12-01	10
傑克	17	2021-13-01	7
約翰	19	2021-13-01	8個
約翰	19	2021-14-01	17

Answer 1

所以我會通過

SELECT FROM Table
    LEFT JOIN Table As PrevDay on PrevDay.Customer = Table.Customer 
        AND PrevDay.date = DATEADD(DAY,-1,Table.Date)
    LEFT JOIN Table AS NextDay on NextDay,Customer = Table.Customer 
        AND NextDay.Date = DATEADD(DATE,1,Table.Date)
WHERE PrevDay.Customer is not NULL 
AND NextDay.Customer is not null

Answer 2

假設列Date的數據類型是DATE您可以使用自連接和聚合：

SELECT DISTINCT t1.Name
FROM tablename t1 INNER JOIN tablename t2
ON t2.Name = t1.Name AND ABS(DATEDIFF(t1.Date, t2.Date)) = 1
GROUP BY t1.Name, t1.Date
HAVING COUNT(DISTINCT t2.Date) = 2;

或者，更具可擴展性的解決方案：

SELECT DISTINCT t1.Name
FROM tablename t1 INNER JOIN tablename t2
ON t2.Name = t1.Name AND t2.Date BETWEEN t1.Date AND t1.Date + INTERVAL 2 DAY
GROUP BY t1.Name, t1.Date
HAVING COUNT(DISTINCT t2.Date) = 3;

如果Name和Date的組合在表中是唯一的，則可以從COUNT(DISTINCT t2.Date)中刪除DISTINCT 。

請參閱演示。