SQL查询以比较计数大于1的记录

Question

我有一个表，其中包含id和answer列，看起来像：

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

我想以某种方式输出，如果用户id曾经回答“是”（例如id 1），那么最终输出应该为1。但是，如果用户id回答“否”和“ NULL”，则输出应该为“否”此外，如果用户ID已回答“不确定”和“否”或“不确定”和“空”，则输出应为“不确定”

最终输出：

| 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'

能帮到您吗？

Answer 2

您要为此使用聚合和case逻辑：

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”，“不确定”和NULL，那么可以采取捷径：

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;