SQL查询来比较有统计记录大于1

Question

我有一个包含ID的表格，并回答它看起来像列：

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

我想输出的方式，如果用户ID曾经回答“是“（例如id 1），那么最终输出应该有1. 但是，如果用户标识已回答”否“和”NULL“，则输出应为”否“ 此外，如果用户标识回答”不确定“否“或”不确定“和”空“，则输出应该是”不确定“

最终输出：

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

Answer 1

你想用聚集和case逻辑是：

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; 

如果只可能是“是”，“否”，“不确定”和NULL，那么你可以采取一个捷径：

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; 

Answer 2

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

这可以帮助你吗？