snowflake-sql - 在特定事件之后的行 FOR A KEY

Question

我有一张如下表，

并且我试图在第一次出现某个键的特定事件+包含该事件的行之后获取所有行，如下面的“xn”（column1），

Answer 1

你见过QUALIFY()函数吗？在这里与MIN()结合使用，并在您所需的键上进行窗口化，效果很好。

此外，如果您想要更快的答案，有时提供用于测试和运行您的问题的 cte 可能会加快答案。

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WITH CTE AS 
(SELECT TO_TIMESTAMP('9/1/2021 10:10','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY ,'XA' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:11','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XN' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:12','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XN' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:13','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XD' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:14','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XT' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:15','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XM' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:16','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'A' KEY,'XJ' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:12','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'B' KEY,'XR' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:13','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'B' KEY,'XU' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:14','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'B' KEY,'XN' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:15','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'B' KEY,'XI' AS COLUMN_1
UNION
SELECT TO_TIMESTAMP('9/1/2021 10:16','MM/DD/YYYY HH24:MI') AS TIMESTAMP , 'B' KEY,'XH' AS COLUMN_1 )
SELECT 
*  
FROM 
CTE 
QUALIFY 
TIMESTAMP >= MIN(DECODE(COLUMN_1,'XN', TIMESTAMP ,NULL) ) OVER 
(PARTITION BY KEY ORDER BY  TIMESTAMP)