SQL查詢以比較計數大於1的記錄

Question

我有一個表，其中包含id和answer列，看起來像：

| id | answer |
| 1  |  Yes   |
| 2  |   No   |
| 3  | Unsure |
| 1  |  No    |
| 1  | Unsure |
| 3  |  Yes   |
| 2  | Unsure |
| 4  | NULL   |
| 4  | Unsure |
| 4  | No     |

我想以某種方式輸出，如果用戶id曾經回答“是”（例如id 1），那么最終輸出應該為1。但是，如果用戶id回答“否”和“ NULL”，則輸出應該為“否”此外，如果用戶ID已回答“不確定”和“否”或“不確定”和“空”，則輸出應為“不確定”

最終輸出：

| id | answer |
| 1  | Yes    |
| 2  | Unsure |
| 3  | Yes    |
| 4  | Unsure |

Answer 1

CASE WHEN (.Answer IS NULL OR .Answer = 'No') THEN 'NO' ELSE (.Answer) END AS 'FILTERED ANSWER'

能幫到您嗎？

Answer 2

您要為此使用聚合和case邏輯：

select id,
       (case when sum(case when Answer = 'yes' then 1 else 0 end) > 0
             then 'yes'
             when sum(case when answer = 'unsure' then 1 else 0 end) > 0
             then 'unsure'
             else 'no'  -- or perhaps max(answer)
        end) as answer
from t
group by id;

如果唯一的可能性是“是”，“否”，“不確定”和NULL，那么可以采取捷徑：

select id,
       (case when max(Answer) = 'yes'
             then 'yes'
             when max(answer) = 'unsure'
             then 'unsure'
             else 'no'  -- or perhaps max(answer)
        end) as answer
from t
group by id;