比較SQL Server中同一列的兩個值

Question

我有兩個表workorder和woactivity 。

create table workorder
(
     id varchar(10), 
     description varchar(1)
);

insert into workorder (id, description)
values ('M37603', 'A'), ('M38440', 'B'), ('M38447', 'C');

create table woactivity
(
     PARENT varchar(10), 
     taskid int,
     result varchar(4)
)

insert into woactivity (PARENT, taskid, result)
values ('M37603', 1, 'PASS'), ('M37603', 2, 'FAIL'), ('M37603', 3, 'PASS'),
       ('M38440', 1, 'FAIL'), ('M38440', 2, 'FAIL'), ('M38447', 1, 'PASS'), 
       ('M38447', 2, 'PASS')

如果我在這兩個表之間創建關系：

SELECT 
    WORKORDER.id, WOACTIVITY.taskid, WOACTIVITY.result   
FROM 
    WORKORDER   
LEFT JOIN 
    WOACTIVITY ON WOACTIVITY.PARENT = WORKORDER.id ;

我得到以下輸出：

id    taskid result
--------------------    
M37603  1   PASS 
M37603  2   FAIL
M37603  3   PASS
M38440  1   FAIL
M38440  2   FAIL
M38447  1   PASS
M38447  2   PASS

但是我想要的是如果每個id的任何結果都失敗，那么最終結果應該顯示失敗，如果id的所有結果都通過了，那么最終結果就是通過-像這樣：

 id      result
--------------------    
M37603  FAIL
M38440  FAIL
M38447  PASS

Answer 1

您可以通過聚合來做到這一點：

select id, min(result) as result
from t
group by id

Answer 2

規則很簡單。 我們按ID分組，按結果排序，顯示結果，其中row_number = 1

;
WITH
cte_tmp
AS
(
    SELECT
        WORKORDER.id,
        ROW_NUMBER() OVER (PARTITION BY WORKORDER.id ORDER BY WOACTIVITY.result) AS rn,
        WOACTIVITY.result
    FROM
        workorder AS WORKORDER
        LEFT JOIN
            woactivity AS WOACTIVITY
            ON WOACTIVITY.PARENT = WORKORDER.id
)
SELECT id, result FROM cte_tmp WHERE rn = 1